Me and a friend of mine keep being surprised how often people seem to miss fundamentals. Sure, they might know the latest incarnation of the parallel for loop in Rust. But ask them about communication overhead -- a basic concepts in parallel computing -- and they're blank.

Similarly, people are happy to see that networking in Kubernetes "just works". Once you ask them to run it on a provider without a Kubernetes-native load-balancer, say just use some BGP anycast magic, they are lost.