It's the season of giving and that's what I'm going to do.
Today we'll be discussing a super easy way to really annoy anyone. To start off, you just need to download a few of those where's Waldo images. Next over the course of am extended period of time, regularly send a person one of these puzzles.
Once they've taken the bait and have started to actually search for Waldo, you should probably wait a bit longer.
And one day, you just remove Waldo. This is where the fun actually begins.
After that first time, you could just start randomly removing Waldos. You could even wait another 5 before tampering with it again or maybe even 10. It just depends on how patient you are.
For better results, wait longer periods between sending the images and send it to as many people as possible. The image alone is context enough and otherwise just think up something on the spot.