I'm a lefty as well and it feels quite natural. The only issue I had was activating siri when bending my wrist but I've deactivated that feature and only use it via voice commands. Sliding the watch back a little helped but deactivating the crown for siri was the best option for me.I, too, am left handed. I will have to try that… though after 8+ years of using the Apple Watch I have gotten used to it the other way.