After installing macOS, you might want to install a few Applications for your Computer to tweak OS X.
Little Snitch is an awesome privacy protector cause, It monitors all apps that are using your internet connection. You can deny and allow internet access to apps if you wish to, this saves a lot of bandwidth and you can track apps that might be spying on you.
MBBench is an application to monitor the real-time speed of Your disk or Flash drive (SSD, HDD, USB Speeds)
Desktop Utility is a very useful Application to deal with hidden files, easily Show Hide, Hidden files, Desktop and Your ~/Library folder and also you can hide your Desktop icons too.
I prefer Mplayer OS X Extended to Play videos on Mac Instead of
VLC, QuickTime doesn’t support MKV, AVI Files.
Well, Macs doesn’t support Night-mode(Before Sierra), Save your eyes for later Install Flux, A must needed application has features better than Apple’s built-in Night Shift mode, Flux has features like movie mode, temporarily disable, color effects and etc.