If you think quitting weed is hard, try quitting coffee if you have it every day. For me, suddenly quitting coffee results in severe migraine headaches and I can't do my job well. Extreme irritability and fatigue, it's truly a stimulant drug withdrawal. It takes about a week or so to get through it, and having green tea in its place is the only way I can reasonably taper down.
A similar kind of thing happens if you suddenly stop smoking weed when you use it daily - cold sweats, irritability, but it only lasts about a day. Anyone who has struggled with caffeine, alcohol, or amphetamine addiction (yes, including ADHD pills), who has gone through a cannabis withdrawal will be pleasantly surprised for lack of a better description at how short-lived it is. I believe that's why so many stoners exclaim "I can quit at any time if I wanted", it's not that big of a deal.
I really believe the negative effects of over-consuming caffeine (irritability, cold sweats, heart racing nervousness), and also the effect of withdrawing from caffeine, are both more severe than either with cannabis. Because caffeine is an accepted daily-use stimulant in our society, I compare it to that.