Let's list the three factors that would maximise your enjoyment of this movie:
1) You love every film ever made by Rob Schneider, the Farrelly Brothers and Adam Sandler. 2) You still giggle every single time you fart in the bath. 3) You're planning on getting beered up and watching this on Friday night with a few mates.
Now, even in this optimum environment, you're still only going to laugh four, maybe five times. But what do you expect from a script by the guy who wrote TV's Men Behaving Badly - the quickly dumped US version?
The joke (note: singular) here is that Rob Schneider gets to act like various animals. When he sees fish in a tank, he goes in teeth-first; when in water, he swims like a dolphin; when he sees a gorgeous woman, he humps a fire hydrant, and so on. What animal actually does hump hydrants isn't fully explained, but with all of nature to choose from (he's been resurrected using animal organs, you see), it's largely irrelevant. The point is that he used to be a reject, but now he's in luurve.
The love-object in question is newcomer Colleen Haskell, whose only acting qualification is that she didn't win US TV show Survivor. That hers isn't the film's worst performance gives you some idea of the low standard.
Annoyingly, Schneider can do funny really well, making people laugh with him as well as at him. As ludicrous as Deuce Bigalow: Male Gigolo was, he sold his man-whore with a heart by coming across as funny and endearing. Sadly, the sloppy direction and gruntingly forced nature of The Animal's gags leave him floundering through one embarrassing situation after another until the contrived ending puts him out of his (and our) misery.