Now I'm rude

J told me to call him, so I did. I called and just directly asked if he wanted to study or not....and he thought I were being rude. How rude is that? The reason I don't say useless crap like "What did you do on the weekend?" or "What are you doing now?" is only because he gives me the impression that he's a busy person so I tried to make it short. That's why...but that's apparently rude?!?!