Meditation on a Theme by ...
Looking around at my overflowing bookshelves, my son once said: "I think you have all these books because you are trying to convince other people that you're smart."
After thinking about for a second or two I replied: "No, I think I'm trying to convince myself that I'm smart."
Maybe it would be closer to say that I overestimate my intellectual ability to assimilate the books that I buy. I'm going to guess that the really smart guys in physics don't buy many physics books. Feynman, Fermi, and Landau reputedly rarely read scientific papers - they just needed to hear the idea and then they worked it out for themselves. Math might be a slightly different matter.
Whoever we are though, we rarely lack the instinct to try to impress each other. It's probably a key instinct in our organization as a social species. Feynman and Gell-Mann made spectacles of themselves in their juvenile versions of dominance displays at Caltech Physics colloquia.