Not all time skips, but I hate when a story ends with a long jump in time and the epilogue is just a thrown together "Where are they now?"
Mostly because due to the way stories go, the time skip is always after the "final showdown" and realistically the characters involved would have a lot of trauma or at least be affected by the events. But a lot of time skips ignore that and push the "Everyone is fine and lived happily ever after". Which I think is utter BS.
Izuku literally saw his childhood friend turned bully turned rival turned friend again die. Katsuki died. Shouto had to watch his brother slowly die surrounded by medical equipment. Hawks lost his quirk. Aizawa lost a fucking eye and a leg. There are definitely others but you get the idea. Sure these kids were being taught to become heroes, but there's a difference between dealing with daily run of the mill villains and being in a war.
I'd rather it have left off on an open cliff hanger, maybe throw in some of how society is changing, but to skip over them healing from the war? Why? We built up to this, why just brush off what happens after?