Enjoying the commentary so far guys but one quick distinction.
In the idea that this predated Reality TV as a phenomena, that's really only partially true. MTV's The Real World had been on the air for 6 years by the time this movie came out, and PBS "An American Family," predates this by about 25 years.
And while a large portion of Reality TV is quite sensationalistic and trashy, at its best reality tv has some merit. Keep in mind, An American Family was the the first time an openly gay character was on television, which is even crazier considering it wasn't a "character," at all but a real person.
Also, while this was Jim Carrey's first real dramatic role, 1996's "The Cable Guy," was a fairly dark comedy, and stretched his talents a bit. Also per Steven's comment that Jim might have had a fucked up childhood...not really. While his family struggled a bit financially, he was very close with his whole family, especially his father. Instead of watching a lot of TV, the family put on little shows in the living room. That's where a lot of his performance instincts come from.