Look around and be careful, because Be Nasty Day is celebrated on March 08, 2018. Nasty is synonymous to being not nice, and that's the reason why most people would be happy if you don't celebrate that day... If you do, please remember that there's a huge difference between being not that nice and being cruel. Not being nice on Be Nasty Day might be possible by switching salt and sugar for someone's coffee. The origin of this day is unknown. Need some help in being nasty? Here you go: Answer the phone when it rings and than hang up without listening to the other person. Or how about telling people what you really think about them? This can sure be quite nasty some time. But remember, be nasty not cruel.