Greed and fear is in every market. I don't think bitcoin traders or investors are inherently more "greedy/fearful" than those who trade stocks or oil.

I think the market structure itself makes people more reactive than they should be. It's an unnatural level of volatility for humans to deal with. There is so little "work to be done", so to speak, to create pain. Whether it be pain of loss or pain of missing out the next move.