The hotel rant scene in Planes, Trains, and Automobiles is so memorable in how it balances perspective without choosing a side. It hits so many kinds of emotional levels.

From Neal's POV, we totally understand where he's coming from. Dude was subjected to so many inconveniences either from Dell or outside circumstances. His breakdown is the explosion of his pent-up, in the moment, justified anger. The scene then quickly pivots once he goes from complaining about the inconveniences Del has caused to verbally assaulting Del as a person, calling him a failure as a human being. Unreasonably harsh. There's a difference between criticizing a person's actions and attacking their character/integrity.

It makes Del's response to the tirade so savage in a subtle yet impactful way. Rather than respond with anger and volume, he expresses genuine, heartbreaking hurt which is such a gut punch. His monologue strips Neal of all his justifiable anger and replaces it with overwhelming shame. In essence, its the ultimate ethical checkmate and a moral defeat for Neal. Like in his monologue, Del could have chosen to be a cold-hearted cynic like him, but chooses not to because he doesn't like to hurt people's feelings.

Without revealing the plot twist, Neal is forced to confront the reality that what he suffered through were just superficial wounds while Del has perpetual injuries. One is temporary and situation-based while the other is chronic and more permanent. You don't know what a person is going through so think carefully before reacting. Justified anger doesn't justify cruel behavior

To bring it all home, the ending is such a fantastic culmination of an adventure where Neal and even Del learned important lessons from each other. Neal went from being Scrooge to Santa in the sense that he gifted Del with something more precious than any physical object; family, warmth, and a sense of belonging.