well if you know that this joke is not funny when you have said it to people more than one occasion, one would be inclined to stop saying it. when joking around, you're not doing it to seek the girl's approval, you doing it to amuse yourself. you're not a court jester entertaining people, you're entertaining yourself. so if a girl doesnt find it funny, respond with "You didnt find that funny did you?" Oh well i guess this will never work out". this will indicate to her that the remark was not for her to approve but for your amusement and you teased her by disqualifying her as girlfriend.
but in the future, use some more obvious jokes and when you're doing gaming on a girl, gauge what kind of humor do they like and use it to your advantage.
Hope that i have helped. Happy gaming dude
