Are Tight Jeans Bad?

They lack functionality 

Originally, jeans were made as workwear for miners. They were made for them to squat down, move easily, and experience freedom of movement when they're working or panning for gold. 

In skinny jeans, doing those things can be difficult. Once you bend over, you're not just exposing your backside area. The fabric continues to stretch and constrict your legs with your every move, giving you little or none freedom of movement.