What was David's mistaken assumption?

David Goggins's mistaken assumption was related to his fear of sharks. Despite being a Navy SEAL who frequently spent time in the water, he exhibited a notable fear of sharks. This was somewhat amusing to Andrew Huberman, given David's extensive waterborne experiences as part of his military training and activities. The fear was evident during a lab visit where David participated in a virtual reality scenario involving sharks, which he personally found quite intimidating, yet he chose to face it as a form of self-testing 1 .