He showed a measure of kindness to Joel, Mike and the bots, a weakness Dr. Forrester attempted to remove by decapitating, killing, and subjecting Frank to countless experiments which were just as painful as the movies. And Frank kept coming back (of course, Dr. F kept the door locked).
But now Frank has been led to a higher plane of existence by Torgo (I can't believe I just said that) and there he will remain, as well as in our memories. We shall miss you, Frank. And yes, we will ALWAYS want fries with that.