Bobcat Goldthwait is probably best known as being that comedian with a high-pitched voice. However, his comedy career ended about 20 years ago as far as I can tell, and he seems to be primarily a television and movie director these days. Or, alternately, a panelist on the radio program Wait, Wait... Don't Tell Me!
This is the first movie of his that I've watched. Short review: wow. It's not a perfect movie, but if you like dark comedies like Life Aquatic, you'll probably love World's Greatest Dad. It was hilarious and poignant. You can watch it easily on Netflix.