I'm light brown skin and my skin color changes to dark brown if I'm hot or if I'm mad. It's annoying because my eye color goes to dark brown when it's hot and goes to hazel in the winter. I also get sun burns on my arm smh how would you feel if you had this to happen?
Reading the title, I thought "What? like I'll turn purple if I find something disgusting?" well, it would be easier to guess what people might be thinking of at the moment.
But with your extra details, I think it's fairly normal with some people. In the winter, there's less sun so the eye color can lighten up. And the skin color, maybe it's because of more blood that was triggered by your emotions that made your skin look darker?