Well Runescape has it charm I am sure, tried to play it once but it never really got its grasp on me, but it wasn't that of an hardcore game, very casual. From what I saw was the community also very friendly.
As for the worst game I would have to say "Bloodwings: Pumpkinhead's Revenge"
Saw an review of it and had to try it out, I regret that I did. The game really gives you no clues what to do.