I started using windows 7 in 2012, and it was one of the best upgrade after windows 98 and abject failure of Windows Vista.
The things I liked about windows 7 were:
1. It was the perfect combination of security and ease of doing work. The OS completely resolved most of the vulnerabilities which were present in earlier version. Now, one can not modify any file in the system folder. The permission level became much stricter and we were able to assign roles and permission to each file and folder.
2. The previous versions suffered a lot from virus infiltrations, as windows were known to be home of malwares, bloats and virus. It was very easy to double click any file and install a virus by mistake, however this OS came with antivirus out of box and with improved file system and antivirus present, it was finally able to resolve all the virus and was even able to recognise suspicious activity.
3. This was the major upgrade where the user interface was made smoother and touch support was provided for devices.
4.Windows Defender and Microsoft Security Essentials came right out of package. This completely changed the game for windows 7.
Instead of all these updates, it used to run smoothly in 2 GB ram and never felt bulky like windows 10. Review collected by and hosted on G2.com.