Front blinkers got to be BELOW the headlights on a truck.
Back windows on sedans need to be convex. Even if just a little.
Speaking of sedans, gotta have a trunklid. A REAL trunklid - not a tiny strip across the back of the car. (looking at YOU, CT4 & CT5 Caddys).
Little bit of a bulge/flare to a fender is good.
Outer edge of wheels/tires even with the outer edge of the wheelwell. Not hiding a few inches in, not sticking out. EVEN.
If you're gonna put humongous diameter wheels on a car, upsize the rotor, too.
Classic trucks just look stupid with 22's and O rings. 15's, maybe 16's, that's about it.
Classics (50's,60's, etc) - just say no to LED headlights that look like magnified spider eyes. Same with "rows of LED's" taillights. It's just wrong.
C8 Corvettes...I mean, they try SO hard to look like Ferrari's, and don't pull it off. The "great wall of China" center console...why?
Pickups - please, no more 4 doors. Rear wheelwells need to be centered in the bedsides. Proportions, people - learn them.
Speaking of pickups - Maverick, no. You're not. You're a Ford Flex with part of the roof missing.
Bronco "Sport" - no. You're not a Bronco anything. You're an Escape having an identity crisis.
4 cylinders don't belong in full size pickups or pony cars.