In a Youtube Video by author AnotherRoof, the author described Descartes as an "arrogant" person who is right, quoting the sentence "I think, therefore I am". However when I am trying to find reference, it seems that the sentence comes from one of his thought experiments where he denies the existence of his body and therefore proves his mind is of true undeniable existence. I also read through the Wikipedia article about Descartes but there is no reference that he was an arrogant person.
To clarify a bit more, I understand that the sentence "I think, therefore I am" refers to a thought experiment and is not an evidence of his personality. I also understand that in the video the Author pointed out some other quotation of Descartes's, most of which indicates a rivalry between him and Pierre de Fermat. However none of the quotation shown in the video appears to me that Descartes was arrogant, rather than being logical. The author in the video talks in a way that seems to imply that Descartes is well-known for being arrogant at the time, and the author is a pretty good mathematician so I would think there are some references about this "fact". I tried to find reference about his personality but couldn't find any.