No way man, you just THINK people will walk all over you. I know the feeling of course, it's hard being nice. But when you really do it all the time people are pretty much shocked at your trustworthiness and respond with their own kindness. Maybe it depends who you hang out with though.

To each his own, but I have found being sincere and kind all the time to be a personality that works out for me. (So it's not like it's impossible). People find it disarming, and I think they're pretty grateful for it. They're like "oh wait... you mean we can actually be honest and up front for once?"

Even on forums like this, where lotsa people are sarcastic and mean, I try to be that way, and it works out just fine. People always appreciate it and if they don't that's their problem--it just means they're the kind of person who would judge you no matter what you're like, and they probably have their own issues that they're just hiding by being mean or something.

What people don't realize about choosing to be kind is that, once you really give it a try, I mean REALLY care about people, you feel soooo much better about your life. Even though it SEEMS like you're going to lose something or whatever, you're just fooling yourself. Making others truly happy = Making yourself truly happy