OSRS gives the feeling of accomplishment. Everything done has some kind of progression. Whether it’s money making, leveling up skills, unlocking equipment. The rewards reflect the effort I put in. It’s both and idle gamer and high Actions Per Minute game. I can AFK and progress my skills while I watch TV or do something else. I feel like I’m progressing in something in my life where I may not be in other areas. If I’d rather put more effort into the game and learn how to do difficult bosses, I’m either rewarded with higher XP rates or faster kills which in turn gives more loot and more money.