Movies that didn't have sequels, but deserved one or more

Napoleon Dynamite is one of the funniest movies I've ever seen. In addition to the many laugh-out-loud moments in it, I loved the attention to authentic details, such as:

The ridiculously long and tangled handset cord. Those 25' (or even longer) cords were the ticket for more freedom to roam before cordless phones were a thing, but they were always getting tangled up and people tended to trip over them or get caught up in them as someone on the phone walked past them.

The double-exposure Olan Mills type portraits of Kip and Napoleon on the wall (double-exposure portraits were an extra-cost, "deluxe" option fad when I was a kid).

The "Vote For Pedro" T-shirts being made exactly the way cheap one-off or small-order custom T-shirts were commonly made when I was a kid, i.e., pre-cut vinyl letters, Cooper typeface, applied with a heat press, somewhat crooked, on a ringer T-shirt. You could get those made at full-service laundromats and various other places for around $5 (a couple dollars for the blank T-shirt and then they charged by the letter, with Cooper letters from Stahls typically being the default).

In any case, I don't think it needed a sequel. I can't think of any sequel to a comedy that was funnier than, or even as funny as, the original. I do wish they would have included the deleted kickball game scene though, since it was hilarious.