Because in the event that you do, Your Highness will hit the spot. If you are also the sort of person who thinks molester-puppet wizards being given a handjob is the height of hilarity, then, well, this film will no doubt leave you in stitches.
I really wish I had bothered to read a review or two before seeing this (it is, apparently, being given a deserved critical drubbing). I knew from the trailer that it wasn't exactly going to be the film of the decade, but some of the lines were funny enough ('Handle your shit, Fabious!') and the director promising enough that I didn't think twice before proffering forth my $8 for the chance to see a minotaur hump a man whose hair McBride's character likened to 'looking like a penis.'
Aside from being crude, the film really didn't know what it wanted to accomplish (or rather, didn't know how to accomplish it). There's a metallic bird companion, which was obviously included because of the 80's Clash of the Titans. But it doesn't really feel like a parody; the bird flits in and out the same as any character, in a mildly un-amusing fashion, but a clever jab at cheesy 80s fantasy it is not.
Occasional bits and lines do bring a chuckle. There is nothing, however, that warrants seeing this in the theatre. Perhaps someone involved in the production realized this, which is why it's crammed full of action and special effects. Indeed, I was quite surprised at the money I saw on the screen, despite the judicious use of puppets. The best medieval fantasy comedies of all time were fairly low budget (Holy Grail? Princess Bride, anyone?). This movie didn't deserve the budget it got (and is apparently not making much back thus far).
Obviously, the greatest tragedy about all this is the wasted talent involved. I could go on for days about the cast in general, but it was Zooey Deschanel for whom my heart bled especially. Whoever coached her on her accent was a lazy ass; on the other hand, if she'd been raised in medieval England and transported via time travel to the present, she still would not have had anything compelling to do or say while on screen; she was merely there to have breasts and help the nonsensical plot along. I was embarrassed as hell having to watch her attempt, while under a randiness spell, to suck on a dead minotaur dick. Hell, forget Deschanel, I would be embarrassed for any actress cast in a role so shitty.
The only thing she got to contribute was a bit of quite lovely singing, but A., it was way too short for my ears, and B., felt oddly out of place. Conceptually, they might've been going for an Enchanted vibe, but it didn't really come across. As a genre spoof, this movie isn't half-assed - it's quarter-assed.
The music in general was actually quite serious, as were the LOTR-style shots of people walking through scenic mountains. This, of course, did nothing to consolidate the overall feel of a movie in which puppets get jerked off.
TLDR version: In a film rife with magic, the only kind missing was the 'movie' kind.