Go to your home folder in Ubuntu by going to the places setting on your top Toolbar in Ubuntu.
From your Home Folder, go to the Edit then Preferences option. In Preference settings, go to Behavior where you can turn on Single and Double click by either selecting Single or Double-click.
Click Close on the Preferences Window.
Now you only need to click a file, folder, program, or launcher once to open it. This will save you 50% of your startup time (not including loading time) since you only have to click once instead of twice. Plus, your left mouse button won’t break as fast since you are clicking it less.