I didn't drink before 5 (well, not usually); never had a DUI (of course, I don't drive); never been fired from a job as a direct result of my drinking; currently don't need to wake up early in the morning to do anything, so why not drink all night?; all my friends and family do it; etc.
Eventually I started to realize that, regardless of all these things being true, I was drinking far more than would ever be considered physically healthy for anyone. I wasn't sleeping well. And while most of the time I could get drunk and still behave fine, a couple of times I really lost control, becoming mean and abusive, or falling down.
That was when I decided to stop.