When you’re trying to turn a draft into a compelling novel, a thing you’ll often hear from critique partners and agents and editors is that you need to soften your protagonist a little bit. Give them something or someone that they love. Let them show some sort of virtuous actions. And these critiques aren’t wrong. Characters should be multifaceted. No one is bad all the time, and we all ought to be able to convey the softer side of our characters.
But…if your core problem is that your character isn’t likable, I don’t think softening them is the solution, and when writers try to do this, they often end up with ridiculous results. You’ll have a murderer who loves dogs. Or a Wall Street fraudster who loves to listen to the symphony. It all might be perfectly true, but it’s also perfectly beside the point.
I think that in order to make someone really compelling, the solution isn’t to soften, it’s to sharpen. Each character has a story arc that embodies some compelling conflict. In some way, they’re being pulled in two directions. And if a novel can flesh out those two poles and show why they’re so attractive, then I think a character can’t help but be likable. Everything else is just a distraction. If you can’t make us understand why the banker commits fraud or why the murderers murders, then it doesn’t matter how many other praiseworthy qualities have: we’re never really going to connect with the character.