Better performance is important in everything, not just MySQL. I don’t want to wait for my text editor to open a file or perform syntax highlighting. I don’t want to wait for my version control system to compute diffs or update my copy of the code with other peoples’ changes. I don’t want to wait for my code to compile. I don’t want to wait, period.
Two tools I have enjoyed recently are Git and the Go language. Both are fast — very fast. It’s a welcome change after suffering from bzr and launchpad over the last couple years. If there is a slower or less efficient revision control program than bzr, I’m not aware of it.
Go compiles fast enough that it’s even a good scripting language. If Gentoo were written in Go, it would be no fun for its regular devotees to use — who wants to use an operating system that doesn’t give you enough time to savor that satisfying feeling of watching Xorg or LibreOffice compile for hours? You can probably tell that I don’t live for the thrill of watching “> /dev/null 2>&1” scroll up my terminal all day.