I grew up with a group of friends and we known each other for almost ten years. I was willing to go all out for them but after many years, I realise they don't care that much about me. So I don't have any reliable friends. But it could be that I was too emotionally dependent on them, or I expected too much from them. But I have since distanced myself from them because they basically expected me to be there for them all the time when I have my own problems to deal with.
As for stealing, lying and killing for your friends, it's really depends on the situation.