Star Trek Season 2 Episode 24

McCoy: Why don't I get the man who is responsible in the first place? Where's Daystrom?
Kirk: He's with the M-5 unit... watching it. I think it surprised even him.
Spock: Most illogical. Of all people, he should have known how the computer would perform. Of course, the M-5 itself has not behaved... logically.
McCoy: Please, Spock, do me a favor and don't say it's fascinating.
Spock: No. But it is.... interesting.