If you’re used to wearing watches of 42 and 43mm as is common for men, slipping a 39mm piece onto your wrist may come as a bit of a surprise. Like shaving off a beard, perhaps, or sitting in a new desk chair, the newness is a novelty and can take a bit of getting used to.
I’ve been a 43mm watch wearer for several years. While my wrists aren’t in the Rafa Nadal neighbourhood, they’re on the sturdy side and therefore – to me – a larger watch with its greater diameter and weight just looks and feels right. It’s all to do with proportion.