At least my attitude is the legal limits are low enough that 'just one drink' is going to be over the legal limit (this is almost certainly not accurate, but it's my attitude; additionally when I drink, it's usually a mixed drink which are often more than '1 drink' for BAC estimation purposes). If you get a DUI ticket, even without a collision, it's a huge impact on your life: much higher insurance costs, loss of driving privileges, potentially an ignition interlock device which are expensive and inconvenient, maybe some jail time, difficulty at international borders, etc.

I have less than a handful of alcoholic drinks per decade, so it doesn't impact me, but when I would drink slightly more often, I would always be sure to have a transportation plan. Either public transit, a designated driver or a significant cooling off period between drinking and driving.