I agree with people being burnt out but it isn't permanent. If they were to quit for a couple of weeks they wouldn't be burnt at all. I'm sure your memories will still be vague but not close to as vague if you go on drinking binge. If someone were to drink for two weeks straight and someone else smoke pot for two weeks straight, the pot smoker would remember much more (my experience/opinion). Not that, that makes it right to abuse either for two weeks...... but I feel someone can be a chronic marijuana smoker and function in society, where as a chronic alcoholic cannot.
I smoke a fair amount of pot on a regular basis. I would have to say the worst side effect and biggest downside I have found, is how unmotivated it makes you.
If it weren't for that I would probably smoke a lot more.
It's not that I'm lazy; it's that I just don't care.