Tom Hanks. He was great in all those light comedies (Big, Splash, etc.), but then he started getting critical acclaim and attention and wanted more. So he switched to drama, and was in over his head. Luckily for him, and unluckily for us, he made big, pretentious Movies With A Message - the type the critics go crazy over, so he got truckloads of awards. But it still doesn't hide his shortcomings.