Wow...interesting question. Are you overbearing when you disagree? Or you disagreeing with things that are personal opinion?
S - I believe in God
A- You are wrong
is a douche bag move. I don't believe in God, but to tell someone they are wrong because they do. Not good form.
This depends solely on context. In debate, you rarely tell someone they are wrong. It will get you beat like a floundering fish. You lay out your arguments and counters and a consensus is discussed.
Also, for the record "you're wrong" can be very abbrasive. If thats the wording you use, you may just have to work on your approach