Tell me your intuition about the writing, please

It's awkward. The first sentence is a run-on. Commas are missing everywhere. Alcohol is a depressant, not a stimulant, so that's not a good word to use. The last sentence is way too cryptic in my opinion.

I agree with Stuh505 that your construction is awkward, the message obscure, and your sentences are filled with poor word choices. It seems you are showing off your vocabulary rather than trying to write a clear sentence that will communicate effectively with your reader.

Try this:

Life for almost everyone is a long competitive struggle. Few win the race, and the rest are unhappy. Some attempt to find at least the appearance of happiness in alcohol. That sort of temporary good humor doesn't last long, and inevitably lapses into either melancholy or a desire to fight the world.

Like Stuh, I found the last sentence unsatisfying and in need of a more radical edit than just breaking up sentences into digestible chunks.

I agree that the first sentence is clunky, and it is indeed missing at least one comma, between "long" and "competitive," since it is common practice in English to seperate adjectives with commas (more commas could go in other places but are not totally necessary). However, the sentence is not a run-on. All the subjects have predicates and there are no floating linking words. It's just too long.

Thank you all
Asherman's rewriting made it much easier to read.
It is intresting to know what alcohol is about. In fact both depressant and stimulant are the quality of alcohol. When drinking, you get excited in the first place, so it is stimulant, and then you immersed in deeper depression if drank too much. Alcohol is double-faced.

I'm afraid I like the original best.

"Is it well written?" was the question.

The point of view, though I might not entirely agree with it, is well expressed. It certainly flows for me and quite gracefully. I would have placed commas after "occasions" and "cheerful" but it goes alright as it is. I hear it as spoken by a reasonable speaker such as my Welsh friend addressing my prone form in the pub and in that guise it would be a very good laugh. Taffy would shake his head very slowly from side to side in a gesture of resignation as he delivered such a mock remonstrance.

I don't know how he takes it.

We write "demeanour" here.

We've been practicising it in the pub and the consensus is that it is perfect.

Best laugh since Molly fell of the stool.

Vic did "lachrymose melancholy" so touchingly we all ended up rolling around on the floor. Vic's done amateur dramatics you know.