Wow; just wow, the last thing I expected to feel after watching “A Prayer for Mad Sweeney” is sentimental. Thus far, the first season of American Gods has been a wild ride showcasing Neil Gaiman’s stunning world of gods and monsters. My first impression of Mad Sweeney wasn’t entirely good—he’s too arrogant for his own good. Yet over the course of the episode I found myself having a slight change of heart.