As well as double-clicking words to highlight sentences/paragraphs, I repeatedly right-click on any webpage / desktop I am on. A while back I took some time to figure out why I do it and realize that it's an easy go-to for checking performance of your computer (ie system latency). The coolest part about this is that these days all menu items, during peak performance, fade in over 50ms or so and when it beings to slow down its immediately noticeable.

I come from a background of a lot of CLI, especially to remote systems over ssh, and the latency from when i type a character to when it shows up is a really good predictor for the system's IO if its being overloaded.

I guess this is also handy when doing remote desktop or in a VM -- but I never do that.