Well... My username was made a little bit on-the-fly when I found FH about three years ago, since I was just excited to play.
I did want it to mean something, but since I couldn't think of something, I decided I'd throw together some words I like.
White; A color/hue/shade/derp often associated with clarity, honesty, sincerity, purity, soundness of mind. I often relate these qualities, and try to reach for this "ideal" in my daily life. Plus, it's my second favorite color (only next to silvery sky blue).
A light-heart; Someone who, well, has a light heart. While I can get serious and nail down a point of judgment like anyone else, since childhood I have always been more likely to cling to the bright, cheery, optimistic and and lovelier side of things. I rarely linger (lul) around in sadness or anger for very long-- even when I want to stay angry with someone or something. I am a light-hearted individual, and this quality I have seen as a part of my identity since I was little.
Some may associate being a light-heart with weakness, being "lilly-livered," or someone who doesn't have a strong stomach when watching gorey horror movies (granted, I do hate those things, but that's beside the point xD), but I see it as a form of resilience in the face of negativity or trial.
Bad things happen. They may throw me down for a bit, but if I can think myself out of of that funk, look to the next best option, and strive for this to get back onto my feet and running to make the best of what I'm left with, what else could you ask for?
So... Hoping to always be a white light-heart.
I'd considered changing it a couple years back, since I've run into several people who thought it was odd or just random, and I myself had been iffy on it for a while, but I've grown comfortable with it, nowadays. The whole reason for it being chosen is clearer to me than when I made it, and so I don't see myself changing it anytime soon. ^^