Taking care of a 3-month old isn't too hard. When they cry, there's a limited number of reasons:
Julie reminded me of the one I missed: Crying because she needs to burp (commence burping)
Julie pointed out that baby's usually don't tear when they cry. I never realized it but it's true at 3-months old. She went on (in her doctorly tone) to explain: After one month, the baby's tear glands are mature enough to have tears. Tears are usually a sign that they are very frustrated. If they are crying to communicate, then they won't have tears every time. Not tearing may also be the result of dehydration (not a problem with Angelina because she's a very good bottle drinker).
Update: This is my most edited entry. I posted three versions of the Horrible before I was satisfied, and edited the text four times. No more edits (I'm looking at you, the Julies!).