A first-year physics teacher once told the class something that stuck with me (paraphrasing): "Nothing is big or small by itself. I want you to always follow these words with 'compared to ...'".
He: I think we can agree everything below the average between a Planck length and the size of the observable universe is objectively small, and everything above is objectively large. Using the geometric mean, that average is about 0.12 mm. Therefore my penis is actually large.
She: I shouldn't have married a physicist.
The arithmetic mean (what you're thinking of) of 1 and 100 is 50.5.
The geometric mean of 1 and 100 is 10. It gives a sense of the average magnitude.
That's... actually kinda cool to know.