A hour of easy quests and then sitting around town doing nothing all day is not a time sink.
Grinding for small % drops to craft high end gear or for reputation is a time sink.
Running speficic dungeons to get fire resist gear for raids is a time sink
Some of us enjoyed that, with the added risk of while grinding someone could gank you at any moment.
I dont remember a lot of bad/boring moments in vanilla wow. I remember a lot of bad/boring moments in all the expansions though.
Before you say i just hate expansions, TBC was good even though was the start of a lot bad current issues with the game. WOTLK was amazing
favorite expansion. Cata was decent, just seemed to go by quick compared to other expansions
mists of pandaria and warlords of draenor was complete trash. Legion im indifferent to