You don’t consciously set out to put on weight so it sort of creeps up on you. You don’t put effort into getting fat. You just wake up one morning, look in the mirror and go “Geeze, what the hell happened?”.
Getting fat is easy and comforting. You can relax and eat all the glorious tasting things. Losing fat is a constant battle. You’ve got to kill yourself in the gym and resist the temptation of eating too much. Doesn’t mean it’s not worth doing and not possible though!