Pot adds a wild card to behavior. The stereotype of pot smoker as laughing at anything is basically true but not because of any gaining of an actual sense of humor. Pot smokers can become more irrational and thus difficult to reason with when you need to get them to do something.. I have seen them irrationally angry when a tool doesn't work or they hurt themselves. It applies more to kids than adults that I have seen.
Obviously a drunk can be the same, but it is less subtle due to alcohol smell and diuretic effects. Also the hangover and lousy digestion that does not affect pot smokers AFAIK is a personal deterrent to alcohol. Thus alcohol and drunkenness is a wider gap than pot and stoned.