From a reader:
When I was on vacation at Lookout Mountain, Georgia USA, I saw the
Priest wearing SANDALS with his vestments. Yeah – that surprised me,
too! Is this normal?
Shoes are rather new-fangled inventions, actually.
And there are many priests who belong to religious orders which require that they be “discalced… shoeless”. They generally wear sandals.
I would instead focus on what the priest is doing during Holy Mass.