I don't think you 'owe' a movie anything. I think you can not fully understand a film and still enjoy it, and want to know more about it. If you didn't like it the first time, then of course, I wouldn't expect you to watch it again. Thing about movies (and the whole art thing in general) is that it's subjective. But you don't need me reminding you of it.

I definitely don't think Primer is an all-time god mode fucking smash hit of a movie, but I do enjoy it. The zero exposition and grit lend itself well to the atmosphere of the film. I like how complicated the plot was (in classic time traveling fashion) because it rewards multiple views, which is something I like doing. I get the impression you work around/with film to have such a strong opinion on the craftsmanship of the film. Of course, everything isn't executed flawlessly, but I'd hardly go with 'sloppy'. If anything, I was impressed at what Shane Carruth was able to pull together with 7 grand. And time travel movies are just fun, I've always loved them. 12 Monkeys. Back to the Future. Timecrimes. That shit is great. So Primer is right up my alley.

But, I don't understand why me trying to in some way quantify my (or anyone else's) enjoyment of Primer or any other movie would make any difference--you thought it was bad and it's not like someone else's opinion could really change how the film affected you.