IMHO, a person who incites joyful laughter in others probably has some advantage, but ultimately, attraction is a highly personal thing, and any one trait is only part of the package.
Awesome thread, Kireina!
I have to agree with Dino -- humor is very attractive and something I would deem necessary, but it's only one part of the person.
Some people I've been around always seem to fuel their humor at the expense of other people's feelings. Now I'm sure we've all make a joke that we later had to apologize for because we hurt someone's feelings, but some people seem to only be able to "be funny" by making fun of others, and I don't want to be around that attitude (I'm more than enough of my own bad influence.)
There are also some people who are the life of the party, but can never take anything seriously. If anyone remembers the movie "Mrs. Doubtfire," there are a few critical scenes that illustrate this. Sally Fields plays a woman who is married to Robin Williams' character, and they are having serious marital problems. Every time she tries to talk to him about resolving their issues, he makes a joke, and eventually, she just gives up.
After they are divorced, she confides to Mrs. Doubtfire (Robin Williams in disguise) that one of the reasons she fell in love with her husband to begin with was because he made her laugh so much. But, "He never wanted to talk about anything serious, and after a few years, the jokes stopped being funny," as she found herself taking on all of their adult responsibilities alone.
I like to describe my personality as a "dichotomy." One half of my personality loves to quip and make jokes and try to get people to laugh and smile. The other half is bile black serious, and, as an example, I was watching a video earlier about "The Silence of the Lambs" because I've always had an interest in serial killers and trying to understand what makes people snap.
I've also always found it fascinating that many famous comedians admit to struggling with bipolar disorder and/or substance abuse, or that they grew up in terrible childhood conditions. What the general public doesn't realize is that they developed their humor as a shield from the reality they were facing, and the damaged, hurting person still exists under all of the jokes.
This is one of the reasons why I tend to make friends on the surface, but have a hard time forming deeper relationships. Most people want me to be one thing or the other, and certainly not both at the same time, so I basically have to chop off half of my personality in order to be around them. However, I also realize that it can cause great confusion and hurt feelings when I'm caught somewhere between my serious and silly moods (or hitting the "switch" tab continuously,) so I'm trying to work on that.
At the end of the day, I'd love to find someone who can find the humor in a serious situation, then also be able to turn around and have a deep discussion about what happened -- maybe even all in the same conversation.