Clash of clans is good game but,
when you start playing this game you can't stop it, because this game is very attractive so you waist your Time , Money.etc by playing this game.
if you play this game continually, you will get an game addiction with this game like drugs. Then you can't live without this game.
So don't start playing clash of clans, If you was already started playing this game try to escape from this game otherwise this game spoils your time.( In case of student, they didn't get concentration in study)