Inability to tolerate even small levels of frustration. I don't know how marijuana causes this effect, but I have seen it many times. It is the opposite of the emotional flatness of intoxication. While stoned, the user under-reacts to his or her environment. When not stoned, there is an over-reaction.
Small annoyances flare into disasters.
If the lid won't come off the jar of spaghetti sauce, the jar might be shattered against the wall. The combination of emotional flatness and emotional over-reaction are especially damaging to children growing up with a stoned parent. I predict that in the next generation we will have a movement called Adult Children of Potheads. In the l960's, we used to think that it was the harsh laws governing marijuana use that made pot smokers paranoid, not the drug itself. Now, the thinking is different.