15% Improvised
Jim Carrey is one of the most beloved actors in Hollywood. In every movie he appears in, he’s bound to make even the most stoic-faced person crack a smile, even if he’s something as silly as screaming his head off. Many of the scenes in Dumb and Dumber are so far left field that we wonder how writers can come up with that stuff.
But is it really the writers? Or is Jim doing his thing and coming up with hysterical facial expressions and sayings on the fly? He was a stand-up comedian, after all, and he probably had to deal with his fair share of hecklers in a funny yet soul-crushing way on the spot.