I'm selfish and not the least bit contrite about it!
I make several sure-fire desserts that my friends love. Recently, a new friend was added to the main group, and they love cooking. He asked me for some of my recipes, and I gave him one. Well, lo and behold, the next time we had a get-together, they brought MY RECIPE!!!! Fortunately, they mucked it up, so folks knew it wasn't really mine, but still... I can understand folks wanting your recipe to take to other friends or family... but to ask for it and then bring it to the very group YOU'VE always brought it for??? Not very socially acceptable! (and they were told this, fortunately. We've had a lot of fun with their experiments to find their own stash of 'sure fire' donations to pot lucks, though, and they're enjoying not hearing 'Well, Doni does it this way, so I'm sure that's where you went wrong...')
So yeah... I hoard my recipes. I don't mind sharing things like peanut butter cookies or apple pie, but my lemon tarts, pecan tarts, deviled eggs, and my chocolate chip cookies are MINE, darn it!