Stymie Bundy made his fortune by never admitting whenever he got lucky.In the episode where he was mentioned, Bud told Kelly that Al attributes Stymie becoming rich despite being a Bundy to the fact Stymie never got married. However, in a later episode, Al mentioned a "Bundy Curse" that makes Bundys lucky until they admit they're lucky and then the bad luck begins. It's possible that Stymie, unlike the other Bundys, was Genre Savvy enough to simply refuse to admit it when the "curse" brought him good luck. The never got married thing could be either an additional cause or an additional consequence.
Al is a closet asexual.It's often quite clear that he does love Peggy but is disgusted by the idea of sex with her and covers his heteroromantic-asexuality by feigning interest in more stereotypically attractive women yet he never make an attempt to cheat on her with them.
Al hated fat men as much as fat women.Although it's downplayed, Al doesn't hold heavier men in high esteem, either. In "Just Shoe It" when he thinks a local shoe commercial will catapult him to superstardom, he didn't want to be compared to Brando, because "he's fat", in another episode, he admits he loves Urkel, but barely tolerates Carl, whom he only refers to as Urkel's "fat cop neighbor". Also, Bob Rooney, the heavy-set NO MA'AM member, is the group's resident Butt-Monkey and it's implied that out of all of the regular members, he has the least amount of respect for him. Another episode has Al, to pass the time in staying up at night to keep his Dodge safe, imitating fat celebrities by sticking out his stomach, most of which were men.
Al's mother, not Peg, is the cause for his low opinion of women, particularly housewives.Notice when discussing his upbringing, he obviously had much respect for his belated father, but doesn't feel the same way about his mother. He himself admitted that she was an alcoholic who lied to him about becoming the President one day and a neglectful parent who gave him cigarettes to take to school instead of a lunch. Plus, we never hear about what Mrs. Bundy did for a living, which one can conclude that she was a homemaker, or, like in Peggy's case, lackthereof. Granted, Peg did nothing to improve this image of the opposite sex (nor does Marcy), but it's logical that his mother painted a picture of women for him early on.
The actor who played Psycho Dad was legitimately disturbed by Al's letter.Because there's no way every male in the universe of the show can be like Al.
Steve Rhoades was eventually going to degenerate into the character that Jefferson D'Arcy was.The last few episodes featuring him even showed signs of this: he was unemployed, indifferent about getting another job (or at least one that paid as much as being a banker), acting disrespectful towards Marcy/using her for her money, and lazy. Upon Steve's actor, David Garrison, leaving the show (not due to the character's change, but to return to theatre), the writers created a character that was what Steve was supposed to become. Also take in mind, when Steve made his future appearances on the show after his departure, he more or less returned to the ambitious, money-grubbing snob he initially was written as.
Kelly Bundy might not really be Al's child.Peggy had slept around alot at the time of Kelly's conception. The only parental tests available at the time are blood tests which are not as accurate as our modern DNA tests. The blood tests that Al used are only 80% accurate.