Trust issues?

Does anyone else have a hard time trusting people because you've been fucked over so many times before.

I've always been the friend to make all of the effort and do all the arranging and all that shit. These days I can't be arsed for the negativity so if something happens i tend to just block the people and delete the negativity.

I've now been told by one of my "friends" that I shouldn't block anyone ever, I've ruined every single friendship I've ever had, and everything is always my fault...