Don't ask me how I know but...

...glass patio tables make lousy work benches for differentials.

...when cutting out floor boards, it is possible to slice through perfectly good brake lines underneath.

...a lift off hood with no retaining pins in place can actually completely clear the car and land in the road behind you at about 60 mph.

...hoods do not make graceful landings.

...towing a race car with slicks on a chain in the rain at 50 mph can produce a ballet of two car syncronized 360s.

...most two car syncronized 360s end with the cars slapping together.