Name something that is the most unneccesary activities or useless things that you seem to find yourself spend so much hours on in a game.

Mine is:
-Cutting grass in Zelda
-Water berries in Pokémon religiously on schedule
-Never miss a Star Bit in sight collecing it in Super Mario Galaxy
-Break all the possible breakable blocks in Super Mario Bros
-Wander off aimlessly in Xenoblade Chronicles
-Snipe random people on GTA
-Use the Genki Manapult by sucking them in, in Saints Row: The Third

What's yours?

Watching cutscenes

Being/Having OCD. (If this counts, great! If it doesn't...)

Well, I think I have a minor case of that to an extent already; so I guess it counts.

When you activate a switch and then it shows what it opened via a cutscene. Let me find out by myself godammit!!

Come to think of it, I wasted so much time on the first ever Resident Evil just watching doors open... and I played the game thee times!

Saving my game file again when I just did 3 minutes ago.

Another one: exiting all the way to the title screen before closing the game.

It hasn't happened in a while but revealing every little corner of the map. Can't have any obscured spots on the map!

The biggest one I can think of is grinding in RPGs.