I used to get drunk once or twice a week, and I thought it was completely normal ("all of my friends do that too").
Looking back, I now know I had an alcohol problem. It affected my work (couldn't concentrate) and it affected my health (gained weight). I'm still young, so I hope there are no permanent effects from my drinking.
I guess it's different for everyone. I'm fine at work & I've actually been losing weight lately (intentionally).
I think there's a fine line between what's ok and what's not. If it actually becomes an addiction and you "need" it to survive the day-to-day, of course that's a problem. Obviously in many (most? all?) cases the individual is too close to the problem to accurately diagnose for themselves.
Looking back, I now know I had an alcohol problem. It affected my work (couldn't concentrate) and it affected my health (gained weight). I'm still young, so I hope there are no permanent effects from my drinking.