Don’t think you can change it although you could, god forbid, register another username & use that as well/instead of. You could then have arguments &/or slag yourself off when you feel the need or to stimulate a little interest if it gets quiet; possibly a popular "forum" trick!
Seriously Andrew, I wouldn’t worry; it’s more important your user name is synonymous with good advice, little point in having a really catchy one if the advice you give is total carp!