I did that once, in Bristol, going to a party. I carefully listed all the rights and lefts and so on, and found the venue perfectly. And then I left, got into my car, and realised that trying to reverse all the instructions simply didn’t work. The map I had didn’t go as far as my elderly cousin’s house, where I was staying, and at once point I found myself stuck in a deserted industrial estate, where I thought I might have to spend the night, until there was someone about from whom I could ask directions.
I actually don’t remember how I got back, but I did, eventually. Elderly cousin had been a bit concerned about my lateness, but we didn’t have mobile phones back then.