Every now and then (which happens to be very often), your desktop might be cluttered with applications, some of them might still run in the background. Additionally, if you shut down the laptop, the OS keeps the applications dormant and will open them after the next login.

When switching tasks, I usually do a little application cleanup. To make this more efficient, I wrote a shell script that closes a list of apps using grep and kill. Download the script on GitHub and stay clean.