There are any number of truisms brought to mind by “Return to Seoul,” the remarkable new film by director and screenwriter Davy Chou. Certainly, Thomas Wolfe’s cautionary dictum, “You can’t go home again,” is one of them. Then there’s Aesop’s advice to be careful about what we wish for, lest it come true. Also let’s not forget the words of the immortal Richard Penniman Jr., better known as Little Richard, who once mused about getting what you want but losing what you had.