All the time, unfortunately.
I think apologizing seems to be the hallmark of working in customer service. When people are mad, you tend to apologize to them first. Not so much because you're wrong and the customer (who is apparently always right) is, indeed right, but because you're sorry the situation arose in the first place. So. With that being the case, I tend to apologize a lot while at work.
aaaaand I'm also pretty forgetful and clumsy in person, so I apologize a lot for those things too.