What non-canon scene was never shown onscreen, but you're absolutely sure actually happened?
For example:
Dennis, Mac, and Frank have watched Dennis' sex tape with the Waitress together.
Charlie learned The Waitress' real name and just decided not to use it. The amount he stalks her, goes through her mail, watching her through high school - he knows.
Mac has paid or otherwise coerced Cricket for sex.
Somebody has paid to bang Maureen Ponderosa in the morgue.
For example:
Dennis, Mac, and Frank have watched Dennis' sex tape with the Waitress together.
Charlie learned The Waitress' real name and just decided not to use it. The amount he stalks her, goes through her mail, watching her through high school - he knows.
Mac has paid or otherwise coerced Cricket for sex.
Somebody has paid to bang Maureen Ponderosa in the morgue.