Relatively speaking also in terms that Columbo was allowing for that fact when he used the term `good`. In actually he was making a distinction (probably slightly ironically) between the `motive` (that which drives and MOTIVATES the action) and the `reason` (which will never be good).

Also saying the motive is rejection is a bit empty because it can actually mean a lot of different things. In this case we know from the episode Kay's primary motive for just about anything was ambition, it's kind of why she got up in the morning. We also know that her relationship with Mark McAndrews was more like a business arrangement. Rejection wasn't the problem when he said he was leaving that did bother him, she wasn't bothered about not being taken with him. Rejection in those terms wasn't the reason. No, the reason and the motive was that he didn't give her the job which to her she'd worked for and earned and than tried to palm her off with a material compensation which wasn't at all what she wanted. To her her basically broke a contract doing that. In her head she was pretty insulted. It's hard to put it into words because it just boils down to saying she was really, really angry which is hard to entirely convey if you don't share her feelings.
But nevertheless the motive did seem to be anger and good old-fashioned revenge.

I just watched "A bird in the hand" and Tyne Daly's character Dolores was really interesting. Her exit at the end is one of the funniest bits in the whole series.

And earlier in the show, the scene where she refuses to give Greg Evigan the money is really excellent. Her character suddenly became a lot deeper than she appeared at first. I remember being surprised the first time I saw it.

Mrs. Columbo

Kim Cattrall in "How to Dial a Murder" ... At least, she was the hottie I wanted to spend some real time with.

From the perspective of me being a hornball, the #1 choice is Gretchen Corbett, in the bikini, in "Exercise in Fatality".

The most interesting killer is Ruth Gordon in "Try and Catch me".