Sticking a note on someone's back or coating a bar of soap in nail varnish are pretty harmless pranks, but sometimes practical jokes go way too far. Drawing a hard line at the the worst April Fools' Day pranks that aren't funny and should never be done is a good way to keep your friends and family happy. Seriously, if at any point you have to say, "it's just a prank," then the joke failed.
Any prank that physically hurts or seriously stresses out the intended victim is probably a bad idea. Just take a look at the weird world of YouTube prank videos to get a sense of just how far some people will take a bad idea. Then do the opposite. There's a pretty clear line between pulling a good-natured prank and just being mean to another person.
Maybe I sound like the curmudgeonly fun police, but there are better ways to get a laugh with your closest friends, family members, and coworkers. And this can still involve practical jokes. My favorite pranks are the ones that are so lame they just make the "victim" scratch their head and wonder why you even went to the trouble of doing it. So if you want to fill a cubicle with balloons or wrap someone's door frame in cling film, go right ahead.