At thy right hand there are pleasures for evermore (Ps. 16: 11)
He that hath no rule over his own spirit is like a city that is broken down, and without walls.
Proverbs 25:28
Temptations are invaders. They come at the small city of your life, and seek to overthrow it, reducing it to shambles. Someone with self-control (one of the fruits of the Spirit) is someone with a militia or company that is capable of defending intact walls. Someone without that fruit is someone whose walls are broken down, and who has dispirited soldiers retreating through the rubble.
Without self-control, without self-government, the necessary result is that someone or something else is going to seize the power of government. Either you rule over your own city, and keep the walls intact, or you let the walls go, and someone else will rule.
Why would someone let their walls deteriorate? Well, budgets reflect priorities, and some people do not want to spend all that much money on defense spending. They would rather that it go to beer, or concerts, or something that tickles the nerve endings.
Building the city walls requires undergoing hardship, and that of course is . . . hard. But when the orc hordes come pouring through the walls, that also introduces a certain measure of hardship. And unlike the first kind of hardship that you worked hard to evade, this second kind of hardship is hard all the way through, and all the way down.
And this is why self-control should be considered a militant virtue. It builds the city walls. Think of your need for self-control as one of the Israelites following the lead of Nehemiah. You want to be working with a sword in one hand and a trowel in the other.