What makes the end piece taste better?

Generally crispier outside with more seasoning to meat ratio.

It’s where all of the salty fatty flavor and goodness resides. In bbq it’s where the smoke ring and seasoning is.

What @janbb said.
If the cooking method adds flavor, that flavor will be all over one side, as opposed to the outside edge only.

Boiling, for example, removes flavor from the meat, making meat flavored broth. In that case, the closer to the end, the blander the meat.

Another possible reason could be that the juices in the meat are trying to exit via the end. (Bleed out?) Roast/sear/cauterize the end and all the juices that were heading out are trapped in the end piece.
Blood is arguably the tastiest meat. The fact that you cooked the juice/blood outflow into the end piece could count for a lot.

GQ. I’d never thought about that before.

The umami taste caused by the Maillard reaction is more concentrated in the end pieces.

The end part of the meat is a bit thinner as well, which helps it absorb more flavor, juice, and seasoning.