I've had an ongoing debate with a guy who is supposedly senior java dev of 20+ years that doesn't understand the most basic aspects of concurrency, and codes "worked on my local" style and engages in obnoxious blame games with DevOps and infra teams about how his application works totally fine spinning up 10,000 threads on his 16 core macbook, but for "some reason" craps out in production running on a 1 vcpu allocated container. At least a year of back and forth on this and he doesn't understand why. Wish I was making it up.