Human

Definitionally, Featherless biped.

Humans are probably some of the funniest animals on earth. In my authoritatively correct opinion, this is mostly due to our capacity for logic and reasoning. When some other animal does something stupid, it ends there. The stupidity is committed and possibly committed again, but there isn't much more to it. Humans are special case because we are capable of both extremely rational and irrational things. Unfortunately, we like to think that we are only rational. The result is that when we do something stupid or irrational, we often come up with the most bonkers reasoning we can in order to assuage the fear that our actions may not be entirely based in reason. Left unchecked, this can lead to a rather large disconnect between why one does and thinks things and why one thinks one does and thinks things.