(S02E06) Sometimes having guest stars on your sitcom is a boon; seeing well-known actors or other celebrities mix with the established cast is great to watch and makes the episode memorable. But a lot of other times, bringing in a guest star dampens the chemistry of that established cast and slows down the comedic flow of the show, almost bringing it to screeching halt.

This week's HIMYM episode has two guest stars: Bryan Cranston as Ted's touchy boss, and Jane Seymour as Marshall's testy law professor. And, in this case, one guest star gave us a good result and the other gave us a bad one. I'll tell you who's who after the jump. You might be surprised at who I thought was the chemistry killer.