I once accidently ran down the battery on my car when I mid-judged how long I could run the radio for without the engine running. It was 5am and I was in the middle of nowhere. I called the first person I could think of who could help and they came with crocodile clips and recharged the battery. I felt so grateful to be on the receiving end of a kind act. I was also embarrassed that I had let that happen and I learned from it! 
Yeah for sure! It was one of those things that once it happens once then you definitely know the limits of the car's battery power without engine running - so you make sure it won't happen again!