Hate:

• Un-skippable cutscenes or tutorials. This really hampers replayability of missions/quests, or even entire games in general.
• Artificially limited customization in order to sell more via micro-transactions.
• Time-gated features. I hate it when games require a certain amount of in-game time before some things are unlocked.
• Pay-to-win in multiplayer games. Preventing or limiting progression with ability to bypass it with a purchase is just gross. If you want to go F2P, do it all the way. I'm fine with for-purchase cosmetics, but getting a leg up on fellow players if you can afford it is just bad.

Love:

• Don't have anything specific. Anything that sucks me into the game.