The morning after hangover is an absolute myth in my case, having consumed cannabis all my adult life ,I never had a problem getting out of bed on time, being punctual or with forgetfulness ,I think

.
Put alcohol into the equation and all bets are off, even if I had say a can of lager in the evening ,i'll wake feeling really rough ,headache etc.
Another observation with cannabis and alcohol , I used to find if i drank alcohol and later smoked cannabis this would have a really negative effect, where as if I consumed cannabis first and then had some alcohol it would be fine. A four pack of beer lasts years in our house.
So in conclusion for me and my experience of cannabis, it has quite the opposite effect to a hangover, I wake feeling refreshed and ready to go.