These are principles that I absolutely hate and disagree with. As an indigo with a mission to bring kindness, they are like a thorn in my side.

Don't TRY to do it. DO IT!

I think this is wrong because it has too high expectations of someone.  If you try to do something and don't succeed, it's not your fault.

Life isn't fair.

This one often gets used as an excuse. If someone is mean to me, and I say "that's not fair!", they will use this INSTEAD of apologizing, changing it, and/or making it right. From my experience, this seems more likely to be used by mean teachers/parents rather than mean students/kids (make no mistake, both things exist).