My worst rental experience was also with Enterprise this summer in IBZ. Hired a car, drove about 20 minutes and started getting a low tyre warning on one of the tyres. As it was evening, dark, close to my hotel, left it overnight and checked in. Again, same warning next day. Noticed a nail in the tyre.

Took it all the way back to IBZ airport where Enterprise claimed that, because I'd driven it out of the garage and not returned it 'immediately' the nail is likely to have happened with me driving it (very unlikely so quickly) and I was liable for the cost. And they charged me. I'd had the car about 15 hours at that point.