Do you think this is rude?

Quite often I'll tap on the shoulder of someone to gain their attention. It's always someone I know but someone I know recently told me this may be perceived as rude. I could understand if someone sees it as a violation of their space and so I have decided to stop for now. My sa is telling me Im disliked for doing that, so I guess I'll find another way to get their attention.

via Social Anxiety Forum http://www.socialanxietysupport.com/forum/f24/do-you-think-this-is-rude-339185/