Well, if you don't know what you did and you are concerned that you did something wrong, then you are probably not a bad person. Just the fact that you are concerned over what happened shows that you are compassionate and empathetic because you are wondering what is going on in the other person's head.
It's impossible to tell why that person blocked you after knowing your for 11 years and not giving you an explanation for it. Maybe that friend is the bad person and not the other way around. I'm sorry to hear that it happened; all you can really do is deal with the consequences, or if you know how to access this person through another friend, try that. Good luck, and I hope that it works out for you.
well i have this nickname that these group of kids call me one day i wrote a note (a friendly note) and i believe my friend was tease by it. yet... i don't know you see my friend had a difficult time telling me what the problem. her and her family are giving dirty look and shunning me at the same time and i don't why and feeling uncomfortable by the impact