Of course they don't realize it - because no one tells them about it! The only way to learn and make amends is when someone tells you what you did that's bothering them.

I really hate it when someone gets mad at me and I have no clue why, so I always go to them and ask what I did wrong so I can learn to not do it again in the future.

Then again, on the flip side, there are some people that are stubborn and don't accept such advice... :\