cos you ran outta weed and its leaving your system ?
You're not broadening your horizons? You're not trying anything new or talking to anyone about exciting things? You aren't doing your fair share of dreaming or aspiring to do something different?
Because you haven't bought anything new in a while. Let's go shopping!
Because your not enjoying your life?
You are losing interest in your lifestyle. Find something new and interesting to do. Sky diving, wind surfing, rock hunting. Something you haven't mastered yet, that will take some time and effort on your part.