Nelson Hayward must be a candidate for having the worst motive. I understand what it's meant to be, but why can't he just wait a few days until he wins the election then sack Stone?

Worst motive is possibly General Hollister in "Dead Weight". He might have been able to bluff them as his victim suggested.

I wouldn't exactly call the MOTIVE the worst one, but Abigail Mitchell decides to "punish" someone who might not be guilty, and the story never tells you for certain whether he is or not.

he was guilty. watch the very end

I could argue that either Col. Rumford's motive (preventing his academy from becoming a coed school) or Luis Montoya's (eliminating the one witness to his cowardice in the bull pen) are the worst. However, I guess either was based on the killer's personal code, and often, the odder the motivation, the more surprising the revelation.

I've always thought that Jarvis Goodland had one of the worst ones, IF he just got too greedy to just take his half of the ransom, and didn't have any OTHER motive. But I can't help thinking that he did what he did partly from considering Tony a "weak link." The story makes such a big thing out of Tony being considered a weak-minded person, so I think Jarvis was probably pretty scared of that.

I tend to side with Martin's general summation (after all, we're talking about a TV show here), and while Milo commiting murder to sacrifice his own empire for a pittance of its net worth never made any sense to me, it was coming up with a clear reason why Hanlon murdered Wagner that always kept me puzzled.

Hayden Danziger in "Troubled Waters"?

All he had to do was pay her off

Regardless of the singing skills, Poupee Bocar makes me wonder why he wanted to break things off with her in the first place.