Anecdotal evidence of course:

It's mindless work, mostly. There's little creative work. And you're pumped up on adrenalin.

I spent 2 months in consulting. Here's a sample.

We slept on average 2-4 hours a night. We traded off eating in the morning vs an extra half hour's sleep - after about two weeks, I yielded and did like everybody else (no breakfast, even though the buffet was sumptuous including home pickled herrings I still dream about). The partners/EMs would meet with the client and then tell us the 400 slides that needed to be produced for next week's board meeting, and sometimes fleshed them out. We then put together the slides, and did whatever BS research needed to be done to justify the numbers (quick Google, hit a database, or - before my time - systematic interviewing of 300 people to create the data necessary, yes, the consultants did the interviewing!). An EM put it to me like this: "Are we 20x as expensive as their in-house talent, certainly; but we'll get it done 10x faster, and without any visual mistakes, and that's all they care about."

I took a weekend (yes, "took" a weekend, because we were supposed to work every day, although we could come in at 10am on Sunday to catch up on sleep) to see an opera in Italy. The train did not have mobile reception. I discovered upon arriving in Verona that I had to produce 50 slides - each with 4 graphs I had to calculate - in 6 hours. I did them, emailed them, went to the opera, had an excellent roast beef with Amarone, got drunk on negronis, came to the hotel to find more work. I passed out on the bed from exhaustion and set about doing it on the train back to Zurich (unrelated factoid: on the train to Italy, Italian customs walked through the train and interrogated the only black guy in the wagon).

One of the team members cracked and overslept by one hour one day instead of turning up for the morning cab to the client. She was mocked about it for a month. We ate sandwiches from a vending machine in the client's corridor. Our EM threw a fit once because McKinsey had booked out one of the 5* hotels in town, BCG the other (both working for the same client as us, funnily enough) and we were stuck with the Ibis Hotel. I didn't understand the swearing in German but I still remember the sound of "Ibis Hotel" fired in anger. I thought it was funny, personally I didn't care, Ibis hotel or luxury palace, it's still a bed and a warm powershower, and I can't have breakfast anyway.

Everybody got extremely depressed once when one of the partners went home at 7pm right after posting a Facebook status update along the lines of "Damn, still at work :( :(". Our return taxi (S-class of course) was booked for something like 2-3am...

I made around 2k/month from my food allowance alone because I ate sandwiches and it was no questions asked cash. We had steak delivery to change us from the vending machine sandwiches, but couldn't enjoy it. Ate the steak in front of the laptop. The hotels and limos were awesome, but what is the point of a balcony the size of a small swimming pool if you never see the sun, and what is the point of a 2m long jacuzzi if you don't have time to take a bath? Some people stopped ironing their shirts to get more sleep, I tried to use room service or my own iron and starch because I foolishly thought I had a career to manage (the EMs didn't care, it's not like us junior folks were client facing).

The lack of sleep was physically painful. By the third night all your body would ache, your eyes would ache from behind, headaches were constant, you were in zombie mode. It sucked but you just saddled up and kept going because everybody else did. Visual perfectionism was constant - I was told off for being 5 minutes late to a cab pickup, and for misaligning an object on a slide by a millimetre. After this, you just stress yourself into double checking your work, all the time, sometimes triple checking, even though it's just as painful. You also eat more from stress, so put on weight. One EM put on enough weight in a month to crack his suit trousers, and went to the supermarket during lunch to buy a couple new pairs.

So yeah, productivity takes a hit, but the sheer amount of hours and generally, the type of people who get into these firms (overachieving, slightly hyperactive, energetic, driven) are more productive per hour on this type of work.

At the end of the case, about half the team quit. Aforementioned lady went to the Kennedy School in Harvard and works for the Brasilian government or something. I joined a trading company. The EM moved to Australia to work on miners' strategy, the other EM to Saudi doing more consulting, but with different working conditions (apparently they get weekend business class flights to anywhere in the world no questions asked in that office).

A few months later, I read in the paper that the client had been acquired by a large foreign group. I thought back about what we were actually doing, and I realized there had been three groups: the management, the board and the shareholders. We worked for the management since they had the power to hire us for more cases. We justified their bad decisions to the board, who themselves had to cover their own behinds enough to be able to pretend they did their work to the shareholders. The company's loss in value over two years was a direct result of a bad strategic decision by management which handed over the market to the one direct competitor. The board was also at fault for not thinking about the stupidity of the one decision in question. In my mind at least.

I'm told it's not always like this, that sometimes you're sent to Sydney with a $40k/month expense account and 9-5 "strategy level" work, that after the financial crisis belts were tightened etc. Hell I had drinks in the Sydney Sheraton spa with a McKinsey buddy recently who was doing just that. Nevertheless I'm not going back to this industry any time soon, it's just not worth it when it's not your equity.

Trading was a different type of intensity. After a particularly active day, even though I had worked only from 9am til around 4.30pm (no lunch, no time), I passed out on the train home. Here, a mistake didn't cost you just a bollocking, it cost the company thousands or even hundreds of thousands of dollars (millions were usually gains, after the other side made a mistake, we were careful). I was a lot more conscientious than my predecessor and only made three mistake in thousands of trades, saving the company a lot of money just by doing my job properly on the execution side; I think my biggest execution mistake lost us $30,000 on $10m so not too bad. Initially, I took the habit from consulting over and had dinner at the office, reheating supermarket dishes in the microwave; but the office was empty after 6pm which was a big realization, that these people made a lot more money and were a lot happier than "us consultants" whilst working less. I guess that's when what you say above about quality vs quantity hit me.

What was motivation? Well, consulting firms sell you the idea that you'll be at the top of the world if only you stick it out long enough, part of the elite that you presumably aren't yet (even if born there). I think banks are similar. (I later read Richistan, linked it with observations, and realized this "elite" was really just the lowest rung, the "employee" layer in the multi layered world of wealth; that these employees, if unable to ignore it, generally get pretty depressed about being in contact with the upper layers all the time; that wealth is really a relative, not absolute thing, above having enough to eat and sleep and send your kids to school.)

Ego is a big thing. A lot of consultants/bankers think themselves more hardcore, smarter, better somehow than the plebs (a lot of them are mercenaries, understand the game and go through the motion for the paycheck). You'd hear people introducing others as "it's so and so, he's from GS IBD" and a wave of relief would go over your body as you would think "ok, that's one of us, I can trust he understands, I can really talk to him". Even today, when I tell finance people I was in finance and talk about markets, they relax and get a lot more open. It's funny because that's rarely the case with developers.

Money is another, not the money right now but the promise of big bucks if only (again) you stick it out for a few more years. The high drop out rate is a function of realizing that either you won't make it, or that no money is worth it, or - in fewer cases - that someone with the level of talent/intelligence/drive these companies select for can actually make a lot more money/achievement/impact somewhere where you're not working for someone else. Or you realize that you're living someone else's dream (perhaps one fabricated by careful PR from the firms in question, and peer pressure) and you go on to live your own life.

The funny thing is that entrepreneurs are very respected amongst consultants and bankers despite making - on average - a lot less money and having a lower net worth. Stick it out til private equity or hedge funds and you'll have a shot at billions which is much rarer in startup land. Yes, but those billions have someone else's name on them, and that ultimately makes all the difference in the status pissing contest. YMMV.

I have a feeling this comment is going to come bite me back some time in the future :P