Jonathan on Who's the Boss was pretty bad. He was only there to be the cute kid and they never really made clear what his personality was. Once he went through puberty, he became the black sheep of the family and they made him a complete loser who never got girls, never accomplished anything and was a complete waste of space. After a while, they just stopped giving him screen time because they didn't know what to do with him, and whenever he did get an episode, they just made fun of him.
Last time I checked, the actor (who ended up coming out) worked at a grocery store.