I'm more concerned -read: apalled- that you thought a parent would have the heart (or lack thereof) to name their children Eugene. If my name were Eugene I'd pretty much believe in Santa Claus until well past my teenage years, or at least until I finished school. I'd need a scapegoat, a surefire way of knowing that putting up with all the cruel load of bullcrap that I'd get from the other kids would grant me a top rank at the Nice List, and that maybe my parents hated me for giving me such a name, and I'd try to make it up for them by doing house chores, unwittingly positioning myself over at the top of their thoughts when it came to gifts, probably over an elder going to university that year - much to their dismal.
However, Eugene is not a popular name nowadays, or I like to think so. Still, answering your question, I do believe in Santa Claus: it's called positiv reinforcement. While Aramara is going out into shamanistic and old philosophy discourses, I'd like to take a more down to earth point of view and explain why figures like Santa Claus, the Three Wise Men, the Boogeyman, and other good and bad figures of folklore and tradition are actually reinforcements in the raising of a kid or multiple of them.
Now, I'm not saying raising a kid is easy. I don't have one, but from memories, bitter and resentful parents (mine still like to torment me with things I did over 20 years ago), and what I've seen, I'll have to say it's pretty fu... funny... and hard. Very hard. So why not grab these kids, and tell them some magical man, located out in the woods outside Rovaniemi, Finland, near the polar circle, is watching him like the Big Brother, with a worldwide network of elven spies and fairy slaves (because, let's face it, fairies are the lowest race of magical beings), and manages an Access database with the name of all the Nice and Naughty children.
You don't know how well it works in some cases - that is, when you're not dealing with an extremely rowdy kids, one of those in which you think a muzzle, restraint jacket, and leash are not only justified but required. The positive reinforcement (as well as the negative one, which would be taking their gifts and toys away) is older than the legend of St. Nicholas, much, much more. Which brings me to my next point: now that we've decided believing in Santa Claus (or St. Nick, or Father Noël, or whoever) is actually a good mechanism to educate a child, is he real?
It has been said and proven that St. Nick was actually a person, and must have been quite a good one if he got to become a saint. This man would buy gifts and hand them over to kids (I like to think he visited the orphanages in his town, making the Christmas of many a tuberculositic kid), all out of his pocket. Eventually, and after his death -despite miracles, saint men and women aren't especially longevous, not when compared to biblical figures-, the figure of Saint Nick went on to become that venerable grandpa with a big beard, dressed sharply for their epoch, handing out gifts while parading through the streets. It's still a thing they do in some scandinavian places.
Going back to the original question: I do believe in Santa. I love Santa, or the idea of it. Whenever I see an old man dressed in red (blame The Coca-Cola Company for that image), sporting a long white beard, curly white locks, and lugging a big round belly around at the mall, I can't help but smile. Because growing old sucks, and realizing that Santa isn't really magical, but a fabrication of your parents, is a very disappointing thing, and sometimes we need to reassure ourselves thinking that the man does exist, and will have nice gifts for everyone - because in the end, no kid is naughty enough to warrant a piece of coal, except maybe as a joke.
PS: Santa brought me a new Lego Sar Wars set this year, what about you?
PPS: Also, Riggy, screw you for making me log in.