Proof: he's a badass but he's also a clumsy.. just watch how he falls from his chair everytime! and is not just this, he's intelligent but sometimes he talks like a stupid and being clumsy.
cit: "He mostly moves by pushing his chair in the direction he wants to go even if it ends up with him crashed on the floor." [Source: his MAL Page]
cit: "haha, what a great episode. i love how they make stein badass and clumsy in the style of the show at the same time. cant wait till next weeks" [Comment by an user in Soul Eater Episode 05 Discussion]