What is your most favorite software and what is your least favorite?

This can be any software free or otherwise. Just list some software and maybe show this question to others and ask them and then answer. Some of my favorite software are Open Office, Advanced System Care 3, VLC Media Player and more.Please LIST them and maybe explain why.What is your most favorite software and what is your least favorite?
Least favourite - Internet Explorer (whatever version) - slow and unresponsive.

Favourite - Firefox for the opposite reasons.

oil change

pf changs menu