For me, the great humor is either of the surprising, slightly cynical and jaded kind, or the vulnerable, self-deprecating kind. You end up loving the character, not because he has this dashing wit in these extraordinary circumstances, but because he's bitching and moaning like most people in the audience would be. The best thing I can say is that some of the biggest laughs in my pictures are kind of unquotable. The only reason his sarcastic comments to himself are funny is because he was literally hanging by his fingernails over a 500 foot drop. There's just no way you can sit around and invent that.
Speed is no exception to the rule.
The screenplay, originally written and solely credited to Yost, went through several incarnations and rewrites before blasting its way to blockbuster status. For me, the mitigating factor, what makes it not an unalloyed joy, is that it's not my dialogue up on the screen. It's Joss Whedon's. Fortunately, I love Joss Whedon's dialogue, so I enjoy watching the movie. This naturally leads to an avalanche of notes.