If your characters could talk, what would they say to you?
Would the bad guy yell at you because just when it looked like you were going to let him carry out his evil plan exactly as planned, you pulled it away?
In most cases, if you did everything right, you want a bad guy wanting you dead by the end of a story.
Would the supporting characters thank you for letting them crack jokes and offer advice? Or would they curse you for killing their friends and not giving them the limelight? Maybe they’d just be happy you let them make it through the story unscathed.
All those replies would be fine, because a wide range of supporting characters really can make a story for many readers.
As for your protagonist, you hope for this:
“I hated everything you did to me along the way you sadistic bastard, but it was sooooooooooooooooooo worth it in the end! Thanks.”
If it’s worth it in the end for your protagonist, it will be worth it for your readers — who will thank you by reading your next story.
A neat perspective, one that can help a writer think about the personalities of their characters and the path the story takes. Good reminder.