It is a common occurrence to witness people neglecting the seat belt. After all, what is the use of that piece of elastic rope.
If you think engineers were mad to put that, please get out of this page.
Imagine yourself running at your maximum speed. You feel the air surrounding you, your pulse rate increases, and mbam! you just hit a wall. How would that feel? Not nice at all. Not wearing a seat belt is way worse than that. Why?
A car in town moves at an average speed of 60km/h. That is at least twice the maximum speed of most humans (twice your maximum speed which hurts when you hit a wall).
From Newton's first law of motion, when your car hits an obstacle or you break suddenly, your car stops, but you continue moving. You then break the car glass and slam a wall or another car, then you die.
You should continue wearing your seatbelt if you love your life, otherwise see you in the next life.