What keeps me coming back to RuneScape is that it is like a living organism; always evolving with new challenges and places. There are the skills as well as RuneScape gold the interwoven tapestries that connect the various gameplay elements together, and allow me to go from creating runestones, to exploring dinosaurs. My personal favourite is Archaeology due to the way it integrates exploration of lore with excellent skill progression.
Regarding RuneScape lore - never forget the quest lines. There I've encountered gothic screams in epic fantasy, as well as the desire of one man to bake cakes. I'll never forget all the hours I spent in The Temple of Light, even when I wish I could. Also, there's Old School RuneScape through which I can go back in time to the very first game I discovered and fell in love with.
I've taken breaks when I'm absorbed in an exciting game from RuneScape through the time. The longest occurred when the Evolution of Combat (also known as EoC) was released - the capabilities and action bars were in conflict with the RuneScape section of my brain.
RuneScape but, as always, comes up with a way to cheap RS gold trap me. This time this was Legacy Combat Mode, which was a return to the tick-based warfare of old. EoC and I are in very tense relationships; mostly due to resistance on my end, but I'm trying. Rarely.