That's an interesting question, I don't think a sense of humor would really matter in the ticklish department, but it would definitely matter in the personality department. Unless a ler enjoys telling jokes while he/she tickles a lee I don't think it would impact anything all that much.
I think that's a brilliant question, and one I have never thought of before, but does make a lot of sense. I am assuming we are talking about the lee here. Thus if they are someone who dosen't like to laugh, then being tickled can be something of an assault against their will.
You would think anyone with a tickling fetish would have a great sense of humor. i have however seen some very serious people with little or no sense of humor into tickling. go figure.