At the OP...could you imagine having watched this movie in the theater when it first came out...with no hype? Do you think your impression might be different? Many of the readers here at VGC are old enough to have been there...so it does have a special place in our hearts for being just a little different than all the other crap they release every year.
I would probably have to watch it a second time, this time without the anticipation for the next scene to make me laugh. Based on my memory though, I predict that I would find it average again.
I suppose my example of a funny movie would be one where I could talk to friends and say "Remember that moment where character A did Z? That was hilarious." I sadly cannot think of any moments in TBL that I could use as such an example.