I've been amazed how in the US being sarcastic and stretching it to the limit - specially in work places - was seen as "the norm" and "how you should be".

The result is that very few people trust very few people (and that trust is not very large, its more of a way 'i know this guy who do XX because I have leverage').

That's sad. Working in a sincere environment, with good values, is so much better on so many accounts. And it also pays off. Have courage. Be sincere.