Several years ago I was at an office party when I realised that I wass unable to drive home safely. I had passed out on a table, thoroughly out of it. When I awoke, I was still no use to drive safely. A good friend, who did not have a driver's permit, drove me home very gingerly. I knew the way, potholes and all, but I was too afraid that I could not react properly if I needed to.
Nowadays, even if I have one alcoholic beverage, I will mind it for a long while and then adopt a few fruit juices and soft drinks for the rest of the time until I hand over the drink to a porcelain holder, or I have had a full belly of snacks, food etc.