Too many to list, but I'll try any way
- Filling the oil after forgetting to re-install the drain plug
- Backing out of the garage, hitting the side breaking the passenger side mirror
- Installing FMIC without getting a clamp tight and having a friend come over at 10:30 PM to help diagnose why the car was running like crap
- Shortly after buying the Legacy attempting to refill the washer reservoir but getting the coolant one instead
- Swapping the turbo without draining the coolant/clamping the lines
- Getting sprayed with fuel while finding out that you cannot use the factory fuel rails and bypass the factory fuel pressure regulator
I'm sure there's many more