for me, what it means isn't that I can't have one drink and stop. I can. I've done it hundreds of times.
and actually, that's the problem.... because I have that EVIDENCE that I'm able to stop.... I used it as evidence I don't have "a problem" for many years.
My REAL issue is this; I cannot consistently predict where that first drink will lead. Taken over time, if I allow even ONE drink, my history demonstrates it will eventually lead to an increasing pattern of intake - until I'm right back to binge drinking or daily drinking in secret. Each time a bit worse than the last.
I think for some it is literal; if they have a drink - they will be off to the races on a binge. Every. Time. It was never that way for me. But just like the stock market has skyrocketing highs and devastating crashes - yet over time grows at a constant rate; My drinking too had its "highs" of reasonable use and it's tragic lows of binge drinking, yet over time grew more and more negative in its impact to my life.