We've found that as much as we've enjoyed the first two seasons of The Bob Newhart Show, there have been a lot of duds in Season Three. Not just duds, but some have been pretty depressing in what's supposed to be a comedy.
In this one, an old boyfriend of Bob's sister is coming back into town to woo her, and Howard goes crazy with worry that she'll dump him to return to Tobin (Fred Willard). Unfortunately Fred doesn't really shine in this episode, although his wardrobe does, since they have him wearing a lot of leather.
Howard gets annoying ... well ... even more so than normal, because annoying is built in to the character.
The only real laughs are very late in the episode, and only a couple of them.