This verse has two halves that seem not to talk to each other. The first is almost a sigh: a longing fulfilled is sweet to the soul. The second is a hard diagnosis about fools who won't turn from evil.
But read them together and the connection appears. The first sentence explains the second. It's because getting what you long for is so sweet that nobody lets go, not even when the longing points to the wrong place.
Reflection
1The Bible Doesn't Pretend It Isn't Good
Notice the honesty of the text, because it's rare. Solomon doesn't say fulfilling a desire is empty, or that it's an illusion that never satisfies. He starts with an exclamation of pleasure: it's sweet.
That knocks down a kind of preaching that doesn't work because it isn't true. When someone says sin brings no pleasure at all, the whole audience knows that's a lie, because everyone's experience says the opposite. If it brought no pleasure, it wouldn't be temptation, it would just be an obvious bad choice.
The Bible is more honest, and therefore more useful. It acknowledges the sweetness and argues about the timeline. We've already seen this here: the flavor in the moment is almost always real, and what costs you dearly is the bill that comes later.
2That's Why No One Wants to Let Go
Now notice the verb in the second half, because it changes the whole diagnosis. It isn't written that fools can't turn from evil. It's written that they don't want to.
That difference explains why argument doesn't fix it. You can prove it with a spreadsheet, with a medical exam, with the testimony of people who've destroyed themselves, and the person agrees with all of it, praises the explanation, and stays exactly the same. They never disagreed with you. They just keep wanting it.
And here's the uncomfortable test to run on yourself. That thing you say you want to quit, do you really want to stop, or do you just want to stop suffering the consequences of it? Those are very different desires, and most people are in the second group without knowing it.
That's also why willpower has a short shelf life. It works while the desire is satisfied or distant, and fails at the exact moment the desire gets close and strong. Desire fights desire, and the hotter one always wins.
3Desire Isn't Beaten by Argument
If the problem is the wanting, the solution has to touch the wanting. And this is where the Bible is smarter than moralism.
Ecclesiastes describes the treadmill in one dry sentence: “Everyone's toil is for their mouth, yet their appetite is never satisfied.” Notice the problem isn't a lack of achievement, it's that the achievement doesn't hold. The desire is satisfied, gives real relief, and comes back hungry again a few days later.
Whoever has climbed a step knows this. The position that was going to fix everything, fixed it for three months. The new car became scenery in six weeks. The bigger house brought joy and then became just the place where you live. There's nothing wrong with any of those things. They simply weren't made to fill the size of the hole.
So the way out isn't to desire less, it's to desire better. No one abandons a pleasure through argument, but everyone abandons a smaller pleasure when they taste a bigger one. That's how a kid drops the gum when the cake arrives.