This is obvious, right?

The protagonist is unwashed, semi-incoherent, and wears a bathrobe. He drifts in and out of consciousness. Very relatable for the invalid.

It's just the right level of funny, allowing the viewer to chuckle continuously without breaking into a coughing-fit inducing guffaw.

Also, undeniably awesome (unless you are Peter Merholz who also hates the Disneyland Matterhorn). You can watch it over and over again without getting off of the couch.

Never, ever, ever do as I once did and rent *The Fisher King* when you have strep throat because you think, "Oh, Robin Williams! I need a stupid comedy to cheer me up."