Friction
Also said as UX friction, Interface cost, Clicks to do it
Everything that stands between wanting to do something and having done it: presses, waits, confirmations, screens. Some is deliberate, and most of it is an accident nobody noticed.
People don't decide a game is annoying all at once; it builds a press at a time. Friction on something done once is fine, but friction on something done a hundred times is what they will remember the game for.
Say it
“Changing boots takes four presses and we do it thirty times in this dungeon. Put them on a quick slot so it takes one press and doesn't pause the game.”
Where you’ve seen it
Ocarina of Time's Water Temple is remembered for its iron boots: on the N64, each change meant pausing, going to the equipment screen, choosing them and coming back, over and over. The 3DS remake made them an item you tap on and off, and its director, Eiji Aonuma, said the boots had made the dungeon seem harder than it was.
Not to be confused with difficulty
Difficulty is the challenge you came for. Friction is what you pay to reach it. Making a boss hard is design. Making the walk back to it long is friction, unless you've chosen it on purpose.