hard to say. a lot of it is hindsight and doesn't reflect how I felt when I was there. it can be excruciating until you go from surviving to thriving. or it can be damaging staying in a toxic place too long.

every country I go to has a "honey moon" phase that lasts until reality hits when I'm forced to integrate (learn the language, start working, etc ...). Some countries are harder than others. On one hand I'm tempted to live an expat live (surround myself with foreigners and other people who are outward looking and who have a similar view on life), on the other hand, faster integration happens when facing the reality (and the struggle).

Less money upon arrival limits the honey-moon phase. Too much money could mean prolonging inertia.

These days I prefer Mediterranean countries where things are less "efficient", and I'm forced to adapt to a slower and more chaotic pace. I'm in love (put up) with the "chaos" of Latin countries. But finding work is also harder and requires sacrifices to what projects I accept and salary. Finding a local job with a terrible salary however can be better for the language skills.

It's hard to make an argument for Mediterranean places when most projects that pay well are abroad, so if salary is crucial for you maybe remote work can help.

After my honey-moon phase is over it gets really tough and staying put can be a horror. Having interests outside of work (e.g. history and culture of the place) usually gets me through. And I tend to stay longer if I learned the language and understood how locals live (which for me is the whole point of doing it).

If you build a client base as a freelancer all across Europe (or whatever continent) then the country itself doesn't matter so much. But you may end up without a real "home". I know that no matter how cool I think it is in the first 2 years, ultimately I will want to get out. Knowing my time is limited (e.g. 2-3 years max) allows me to stay positive and appreciate every day at the place I'm at. Usually I have milestones of what I want to achieve before I go there (that are always personal goals and have nothing to do with work. e.g. work is a means to an end and to achieve that private goal)

But to answer your question I'd say I like it anywhere with an ocean, and great food. If the food is bland usually the rest is less appealing. German food is not my thing but history and culture can make up for it. And there are plenty of international restaurants. So to live in Germany happily salary has to support eating out 3-4 times per week. Some places I liked would be Ireland (I dislike Dublin). Cork and Limerick are awesome, Palermo (or Rome), Madrid, Bilbao (I dislike Barcelona), Toulouse, Aix-en-Provence, Lisbon, Porto, Malta, Lausanne/Geneve, Copenhagem, Malmö ... even Eastern Europe (Belgrad, Zagreb) but only with remote jobs and with strictly time-boxed stay.

Some places in Germany are (IMHO) easier than others. Frankfurt is a sh!thole, the best thing about Munich is the highway to Austria (that will lead ultimately to Italy), Berlin is OK depending if you still want to party every night. Aachen & Cologne or Duesseldorf are more relaxed than Bavaria and I find people there really friendly and open. Again Bavaria is a nightmare IMHO. Although Duesseldorf or Cologne can get boring if you are with a partner or (gulp) kids, ... at least for my taste.

Luxembourg can be great but it's built on holding companies and off-shore money, so the scene can get a bit seedy and very banking/insurance oriented. I love Paris (single), but with kids it's a nightmare.

If you don't like Germany try Vienna. It's a bit more laid back than Berlin/Munich, and has culturally a lot to offer. Switzerland is equally cool due to the many meet-ups, winter-sports, mountaineering, great salary ... but can be equally tough as Germany especially if you're not planning on learning German. I think language is key. If I can't motivate myself to learn the language it means I must move on or end up getting depressed very quickly.

Most important for me was learning when it is time to look for a new adventure and when I should linger. There is a reward in sticking to a place (Singapore took me 2 years to fully appreciate and learn to love and I whined for 10 years after we left). Australia was great when I was there. Not sure how it is today, ... it seems they have thrown the tech community under the bus

Wherever you are, not getting out in time can also be very negative for yourself because we get back the vibes that we send out. Or if you're a very stubborn or tenacious person not getting out can also be incredibly rewarding provided you put in the work. Hard to say :)