word of advise:
if for some reason, you don’t want to pickup someone’s call, please make sure he is not around the vicinity. because it would look damn bad if he saw you looking at the phone and not picking up his call. trust me, I learnt it the hard way.
I reminds me of my answering service:
“i’m avoiding someone at the moment. so leave a message, and i’ll return your call. if I don’t call you back, you know that it’s you”