Yes you're probably right in terms of being a first world problem but I have found the slippers in F on EK to be the best airline footwear around because they actually slip onto your foot and cover the whole thing. Unlike some others where your foot is exposed. I'm also confident that because of the dedicated SPA attendant on the A380, the bathrooms are kept in a very clean state. I always carry spare socks with me anyway. Were you on the 777 or 380?