WoW is the ultimate timewaster. It is the ultimate game for losers. You could be a lot more productive by reading books, science journals, history, or learn multiple programming languages. Or workout, lift weights, or do MMA.
Instead what you do is SDAR in front of your screen grinding endlessly so that you can obtain Heroic/Mythic loot from the raids/dungeons. And once you reach an item level that is high enough, heroic and mythic raids are now boring because they are easy.
Now what you do is instead of quitting or playing another entirely differnent game, you decide to level up another character and grind endlessly to reach a high enough item level to the point where heroic and mythic raids get boring and easy. Then you do the same shit again with another character.
By the time you know it, 6+ months have passed and you have not gained in any other aspect of life.
You will eventually quit because you worry about being homeless soon if you don't kick the bad habit/addiction.
Then you get back to playing it within 2-3 years and the cycle repeats.