With the exception of killing Pokémon I'm trying to catch, CHs have been more of a help than a nuisance to me. Except, it seems like half the time I get a CH in a trainer battle, the opponent's HP is so low that it would have fainted with a normal hit... Where was that CH two moves ago when I needed it? :/
Even so, I like Critical Hits. Sure, they're not really useful/reliable, but they help give battles that air of unpredictability that let them feel like battles between actual living creatures, instead of making battles an entirely rote formulaic process.