I had just started being a mobile mechanic and I got called out to an Audi Q8. I was doing the rear brakes on this Audi and I took the wheel off. I took the brakes apart. I go to press the piston back into the caliper and it's an electronic parking brake. You need a bidirectional scan tool to retract the parking brake on that Audi. I didn't have that. I ended up messing around with the brake pedal and I caused the piston to come out of the caliper. I spilled brake fluid all over this rich dude's nice garage floor. He had parked the truck in the middle of the garage blocking the other parking spots and blocking the garage door from being able to go down. I was not able to finish that job. I had to just pack up and leave.