I could not live without Caffeine, it was similar to Amphetamine but not updated for years. What Amphetamine does is simple keeping your screen on on your computer, like it won't start any screensaver and any dim of light while watching a video or you can use it simply to keep your computer always awake in case your downloading important stuff that takes days.
Most of the Mac apps don't need an installation but when you're run them they are spreading files all over your computer that you're not able to see. Just by dropping the main app into app cleaner you will get rid off of all of these files and uninstall the app correctly.
A must have it for insomniacs and not, this app changes the color of your screen based on your location and sunrises and sunsets, so that your eyes don't get tired before going to bed. you can set a wake-up time and it's working for real, you can deactivate the app until sunrise or for 1 hour if it bothers you or you need your computer with the original screen colors.