No to parties if you have an exam tomorrow, how many times did your friends tell you that you will come home early and that party will end up at 11 PM but in reality the party ends at 5:49 am. How many times they tell you that just one more drink and they'll let you go but you almost drink the whole barrel of beer and they still refuse to let you go. Once again say NO, say not to madness.
Say no to toxic relationships, say to no people who uses you. They were only good when they needed something and when they get what they want they will treat you like a rag again. Don't be afraid if you have lesser friends than everybody, people who has a lot of friends tends to please everyone, they wanted to be liked by everybody so they spoil all of their friends, treat them with kindness even if in real life they were really bad.
Saying NO can change your whole life forever, say no to things that doesn't benefit you. Say no to Laziness, say no to drugs, say no to poverty, say no to corrupt government. It is up to you, saying no will not hurt you at all.