Are we talking system gripes or gripes about the actual campaign?

I'm a player in a 5E game and running a Call of Cthulhu campaign.

For my 5E group: no gripes about the way the game is being run. My DM is doing a great job and I'm enjoying myself immensely. The players are all cool people and we get along even when our characters don't. System-wise, I'm getting a little tired of 5E's attrition style combat. Most fights go on twice as long as they need to. Also, I have a lot of cool abilities but I'm afraid to use them because nothing sucks worse having no spells left and no chance to rest.

In my CoC campaign: I'm deeply uneasy about how things are going. It's a long campaign and I've been holding back on the horrors to build tension. Unfortunately, I think I waited too long and it's backfiring. The players are starting to feel powerful, and they're acting more like a D&D group than is really good for a horror game. I'm going to have to scare the shit out of them next session -- someone is definitely going to die in the worst way possible. I'm just hoping that popping their power balloon this late doesn't cause the whole campaign to run aground.