Is noticing them.
The game I'd mentioned in my previous post, Escape Velocity, has a fair bit of grinding. The safe ways to make credits, and the only until you can afford a combat-ready ship, is to ferry trade goods between systems or to run delivery missions. It's a grind. Back when I first got it I had no concept of grind so it didn't seem all that bad. Since then I've learned of grinding and suddenly I found myself bored.
Alas, if only I didn't know I was supposed to be bored!
For all its negative effects, ignorance is so often bliss.
"Death solves all problems - no man, no problem." - Joseph Stalin
Ignorance solves all problems - no clue, no problem.