I wasn't going to go see this at first, because I've always been a devotee of the BBC radio series (which I had recorded on cassette tape), the tv series and the books (including a book of the radio series scripts). I'm almost a Hitchhiker-nerd, except I don't tend to quote the funny bits (because I can't remember them word for word) and I've never felt the urge to attend a science fiction convention dressed as Arthur Dent (well, once...but I didn't go through with it).
I'd read bad reviews and good-ish reviews of the film. In the end the only reason we went to see it was because the boy wanted to watch it anyway, just to confirm the negative reviews.
It sure was important to have low expectations beforehand.
Lots of the funny bits from the books etc were in the film - unfortunately for me, they didn't make me laugh because they were so familiar and yet somehow not the same. I suppose it's like going to a pantomine and finding the performers have changed their lines just enough to jar you. And I was so used to hearing various characters speak in a certain way that it felt strange to hear it said differently, by different actors - wrong, somehow.
There were a couple of new funny bits - like when the white mice are about to feel Dent's wrath and exclaim "Bollocks!" (you'd have to be there). Also, the Vogons look really good as hunch-backed beauracrats - but Marvin looked a bit too cute. I was disappointed, too, that the Golgafrinchans didn't get a look in.
Probably the best part was the tour of Slartibartfast's work floor - really nicely done. Probably the worst parts were the lovey-dovey bits.
It wasn't a complete waste of time and money then, although it was just long enough for my infamous sore-bum afflication to return.