In the first film, when the rest of the team decides that revisiting the island would be crazy, Jet Li's character, Yang, insists on accompanying Barney. When Barney asks him what's he's doing, Yang's response is "Friends die together."
Barney may be a cynical and burnt-out Knight in Sour Armor, but upon seeing the joyous reunions of the Russian families with the fathers and sons he has rescued, for the first time in the series his cold exterior finally dissolves to reveal a genuinely warm smile, as if for the first time he felt that the battles he fought for meant something.
Although not an "official" expendable, CIA Agent Maggie Chan reminds Barney at the end of The Expendables 2 with a warm grin.
In a more meta moment, the movies themselves are this not just for the hardcore action fans who love the action films of the 70's, 80's and early 90's, but for the cast as well. Stallone specifically stated that one of the aims of making the film and casting decisions was to give some new work to some of the famous action movie stars of yesteryear.
I like using people that had a moment and then maybe have fallen on some hard times and give them another shot. So we’re always looking for actors like Michael Biehn and Michael Paré. I like those kinds of guys. Someone did it for me and I like to see if I can do it for them.