I don't have caller ID, so answering the phone can be somewhat uncomfortable since it might be a telemarketer, prank phone call, or someone I don't know. Also, I don't know why they are calling me, so it can also make it somewhat uneasy.
But, when making phone calls, I know who the person is I am calling, so I like calling people more.
Same for me, I mainly use the telephone, e-mail, instant messengers,etc when I really have to like "saying I'm sick, and can't make it to school, work, or a party, or if someone is trying to break into my home.
I used to have this crappy phone which always misdial to an old ladies house, and I always say wrong number, but she thought I was prank calling her which I wasn't.