But I like making friends!

In all seriousness though, I think the thing most healers need to learn is that if you ARE going to cast Regen willy-nilly, DON'T RUN AWAY. Running away is instinctual, I know, but it isn't going to help you or anyone else, especially the tank trying to pick it up or the dps trying to kill it. Run to the tank. Run in front of the tank. Stand still even. Unless you get aggro on a hornet that's about to final sting you, you probably won't die instantly. Don't be a wuss and take a few hits.

p.s.: WHM tank is best tank. <3