I asked if that means I also and I also had a mental illness that was causing me to think like this and I was told that yes I do. But noone can tell me how or why that answer is a 'yes'.

Not that you have a mental illness which causes you to think like this, but you habitually thinking like that and the thoughts which support it are the mental illness.

It's possibly hard for you and most people to understand but when you feel out of place often you just want to leave.

It possibly is hard for me to understand, but possibly not. I've dreamed of suicide for a good half my life and got close to it on occasion, never talked about it to anyone (and hence never been diagnosed with anything) and put a front over it. I would describe myself as depressed, but not out loud. I'm also a bit stubborn.

I've seen enough basics about zen and similar that I when I am angry I can notice a part of my head which isn't angry, which is just observing. I've recently stumbled on self help techniques which sound ridiculous and found that just by sitting and thinking in a particular way and counting backwards, fear carried for years since childhood faded like gas from a deflating balloon. A memory which was charged with negative emotion where the mere act of remembering it triggered physical feelings is now just a memory.

Nothing fun I've ever done changed that memory. I never even realised (until recently) that said memory of a trivial event was at all significant or relevant to anything at all, it was just a part of me which occasionally popped up and I tried to not think about it.

It's these things which keep me interested and hopeful. It's these experiences which make me think normal people have completely massively wrong beliefs about many things to do with habits and behaviour. (such as "other people's behaviour can make me feel bad", which is just completely endemic and so basically wrong it's been written about for thousands of years).

Such that when you say:

By now you probably are guessing that the way I'd like the world to be (simple, happy and loving, etc.) isn't the way the world is, and that's very much the reason I don't want to be here.

I say "I doubt it", and suspect you might not even be aware of the reason(s) you don't want to be here - what pattern is it that you learned, that you have stored in your head, that is driving the link between "not simple, happy, loving" and "don't belong, can't wait to leave"? Because not everyone has that link. So why do you have it? (and I also suspect that if you are "most people", you wont know what kind of answer to give to that question or that there could be more than one kind of answer and your brain might give you the less useful one by default).

If this sounds like I'm saying you should just "get over it", I am and I'm not. "get over it" implies you should steamroller through your problems and that is lame advice. I'm saying you should(?) try debugging yourself, and there's a fair chance it would be possible if you learned and practised ways to do it (and I likely don't know what).

Your want to escape and commit suicide is only "right" if you want to be running a program in your head which desires to leave and commit suicide. If you don't want that, it's a bug and should be debugged, not marked as a "feature" and left there. And you don't debug your head by earning lots, driving sports cars and chasing hedonic pursuits. You debug your head by looking at what your head does and trying as many things as you can think of (in your head) until you find something that changes its(your) behaviour.

With the facts given above, is it not possible that I'm just one of those people that see life differently from the norm.

JustIsADangerousWord. Do you want to be someone who sees life differently from the norm?

(Postscript for the detractors: Not a doctor, not your doctor, all IMO, yes I accept that not all things work for all people, yes I accept that some people have chemical imbalances. I don't accept that chemical imbalances are the cause of most people's day to day problems like fear of public speaking, social anxiety, fear of asking for a raise, feelings of insecurity, feelings of worthlessness, feelings of wanting to escape, feelings of loneliness, etc).