Abstraction is expensive

For many computer systems, abstraction misalignment is where we spend the majority of our resources: both in terms of engineering costs and compute time. Most small-scale web services that do normal things don't pay much for abstraction misalignment, but large-scale systems and systems that do odd things pay huge costs. It's easy to see how using the right database schema or picking the right programming language can help you with both CPU time and engineer time, but the abstraction tax hits us up and down the stack. In Google's case, the bandwidth expansion of network cards caused the TCP abstraction to become stale. You can't avoid abstractions as a software engineer - software itself is an abstraction. In a way, software engineers are professional abstraction wranglers. At companies with huge engineering forces, abstraction management is what a lot of them spend their time on.