These guys are terribly cute, and often playful.  They'll come up to you and tug at your fins.  Here are some videos of harbor seals.  

How close will they get?  This close:

Seals eat fish.  This one's learned to hunt by dive light, and will often accompany us on night dives.  I call him Photobomb, because I have a lot of pictures of him eating what I'm trying to photograph.

Seals don't have visible ear flaps, just an ear hole.  If it's got ear flaps, it's a sea lion (see below), not a seal.

Did you know that seals have toenails?

This one's a juvenile which followed us across the cove.  I definitely wouldn't want to get this close to an adult.  Video here.