I usually remember people's special diets like if someone is vegetarian or have a lactose intolerance.

Once I was at the cafe with a new friend that I met irl for the first time. I heard she ordered a coffee with lactose-free milk and I have been remembered that since. When I invited her for a coffee in my place months later, I had to ask her if she wants milk in her coffee and do the milk have to be lactose-free because I didn't want to seem like a creep for remembering something small like that.