What I feel really bad about is when friends who are authors or musicians give me free copies of their CDs and books knowing full well that I would happily pay for them.  I gave the money to one person's manager because she wouldn't let me pay her for the CD.

Of course, I have filmmaker friends who practically have to pay me to acknowledge much less sit through some of the dreck they are associated with.  Mind you, this is more of "my opinion on a particular genre of film" than on their work usually.