Video games are generally designed to be fun, and generally they start out easy. But fun and easy gets boring quickly, so the game gets more difficult and complicated as the player progresses. You can only go so far in that direction, though, before players can't keep up. As an alternative, games will often substitute repetition for difficulty. And that's where the game becomes work.
That's not to say the grind is always bad. If you're in the game to play with your friends, and you're all doing the same things together, that's a good reason to keep going. Or if you actually enjoy the repetition, by all means, keep going. I find that pretty rare, though. Friends eventually move on to other things, and the most enjoyable gaming experience gets old after doing it for enough days in a row.
Sounds like there's a simple solution...just stop doing it! Ah, but it's not that easy. You've invested a lot of time into that character. The game provides some kind of carrot...better gear, nicer base, fancy titles, etc...that you're working toward. You see other players who have kept up the grind, and want to get where they are. Often there's new content...another raid, another dungeon...that you could open up with enough work. Stopping means giving up those possibilities.
The best way that I've found to break that grinding cycle is this...rather than thinking about stopping, look ahead to something new. Another game, a TV series to watch, a book to read, going on a trip - there are lots of things that can take the place of going back into that game for another round of daily grinding. Once you get involved in the new thing for a few days, that grind looks less and less important. Before long, you'll be happy that it's no longer on your mind.