People sell because they don't understand Bitcoin and its market. The general noob logic is that Bitcoin can become worthless overnight, which triggers these panic sellers to sell now in order to not lose everything. Funny thing however is that they are eventually going to buy back their coins once the market is going up again, but then with a massive premium. Instead of preventing further losses, they are burning through their money even further, because it's a never ending cycle for them -- it's pure capital destruction. I happily buy the market down as much as I can, and for that reason buy in smaller fractions per time to not lose out on even cheaper coins.