You know what I loved? It was an easy, quick, completely whimsical read with some laugh-out-loud moments. Almost every line delightfully charming, it's easy to see why this is a classic with so many pale imitators.
You know what kind of sucked? Nothing about the book itself, but how my experience of it was altered by the fact that I'm definitely not the first person to think it's awesome. The first time I saw the movie, I don't think I even knew it was based on a book. It's one of those pleasant watch-it-if-it's-on kind of movies that I've ended up seeing a handful of times – the upside of which is that I had Arthur Dent cast firmly as Martin Freeman in my mind, though back in the days before Sherlock Martin Freeman was only in my head as That Guy Who's Very Very Good At Playing Normal Guys.
The massive downside of knowing the movie well is that a lot of stuff was spoiled for me. I even remembered exactly what the bowl of petunias falling onto Magrathea was going to say. Though the ending was quite different, which was a pleasant surprise (remember back in the day when people used to actually adapt stories for screenplays instead of just making sequel after sequel?) and it certainly ended on a bit of a cliffhanger, so I'm keen to read the rest of the series.
You know what was weird? Theoretically, I shouldn't have enjoyed it. It broke a lot of rules that usually make fiction unbearable for me: there was a ludicrous amount of adverbs, it was sorta sexist*, and the narrative voice had that slightly mocking self-aware tone that usually makes me want to rip my eyes out when amateur writers attempt it. But somehow, through magic or, more likely, mad skills, everything works, because the story remains anchored to an unpretentious style and a fiery, confident imagination.
I gladly give it 4 / 5. Adams got through my stylistic hang-ups by charming my pants off, and I liked it.
*I say sorta sexist because the only woman in the story (and by proxy, in the galaxy) had no agency, no opinions, no impact on the plot whatsoever. Hell, she barely got any lines. It irked me.