^Well, yes, that's just it -- her snide, acerbic comments are often real zingers. I'm not talking about humor in the sense of laughing at knock-knock jokes, but in the sense of dry sarcasm and biting comebacks. A typical Vulcan would just react with incomprehension or excessive literalism when a human says something illogical or impertinent, but T'Pol will wither them with a sardonic reply. Maybe it's more "wit" than "humor," but it's definitely there.
I can agree with that. Back to the original question of getting a good laugh, you might get a giggle or two from talking to T'Pol but not a good laugh. Whether or not it would be entertaining to try to get her to laugh, it would probably get frustrating quickly since, unlike the Buckingham guards that would want/enjoy a good laugh, you would never succeed with T'Pol.