The Series 3 is thicker though. I’ve heard the 40mm Series 4 feels smaller, or at the very least, similar.

EDIT: apparently the 40mm size is also just a lot closer to the 38 than 42, not right in between, due to how the numbers are rounded. Side by side photo here https://www.reddit.com/r/AppleWatch/comments/9iecba/38mm_vs_...

My wife still thinks those things are huge.