It might feel good now, but soon when you are bored and tired of clicking 1000 times on 'whats new' while there is nothing new to reply on anymore you will go back to www.runescape.com 'just to check out if there are new things ' and you will be addict again!
It's not that difficult to quit (was easy for me). Just let your membership run out and never pay for it again. You will experience that F2P (if you haven't already) and quit. Worked for me.