Over the years there have been countless great ideas for customizing stock vehicles. Inevitably, there have also been some real losers. What modifications have you seen that have been horrible, dangerous, or just plain pathetic? I'll start it up with some Golden Oldies.
Rear shackles on 1960s and 70s 'performance' cars.
The idea here was to hike the rear of leaf spring equipped cars to ridiculous levels so you could install super wide wheels/tires without the hassles of wheel tub modifications. What you ended up with was a dangerously unstable vehicle due to the higher center of gravity at the rear and changed steering geometry on usually already worn out suspension components at the front. On the plus side, you were always driving downhill.
I rode in one of these cars. Once.