The worst feeling is when you progress the main quest by mistake while trying to clean up side things.
Dead Space has that really cool diegetic "locator" system so if you come across multiple paths you can see which way points toward the story, and take your time exploring the other direction, knowing you won't accidentally start a story cutscene that locks you out of explorable areas
Ludonarrative dissonance overdose when the main quest is about hurrying to save thousands of people from an incoming disaster but the hero keeps playing card games with everyone they meet
Speaking of card games, my favourite example of this is Witcher 3.
I GOTTA FIND AND SAVE CIRI, SHE'S IN TERRIBLE DANGER! ...but first, Imma collect every Gwent card
Me with BG3 right now. Every side quest feels super important or at least engaging!
me playing botw, getting the master sword, and then instead of finishing the main quest, proceeds to destroy every guardian in hyrule to get the ancient armour while also doing shrine quests on the way lmao. the gorons can wait