Hendley and Colin may not have seen eye to eye (no joke or pun intendid) about a lot of things but Hendley stands up for Colin just before the breakout.
Hendley: Colin's not a blind man as long as he's with me. And he's going with me!
While most of the ending is both Tear Jerker (because of the fifty deaths) or awesome (because Hilts and some of the others survived), hearing ol 'Cooler King' Hilts throwing that baseball at the wall once again gives reasons to smile. It makes the audience remember that while the men went through a terrible tragedy, they will endure... and they did.
One of the camp commandants who replaced the man in charge at the time of the escape was so disgusted with the Gestapo's actions that he allowed the inmates to erect a memorial to the fifty outside the camp. It still stands today◊.
Louis' dedication to making sure Danny escapes with him (much like Hendley and Colin above).
Willie catching up to Danny when the lights go out, and calming him down.
Hilts showing that his cockiness is in part a facade when he sacrifices his own escape for the greater good. Quietly reinforced later with a nod when he's released from the cooler after he was unable to save Ives.