I worked part time as a limo driver for years. Meryl Streep is probably the most famous I've driven. With few exceptions celebs didn't tip well. Plus it was usually a pain in the ass as my boss would constantly check in to make sure everything was ok, and sometimes they would give me fake names or not give you actual pick-up location until the last minute. I'd much rather drive regular folks out for a night on the town, better tips and less stress.