The "magic eye" stereograms that became popular in the 80's frustrated me to no end. All my friends saw the 3d image within seconds while I sat there all day, anxiously defocusing my eyes until they crossed.
When I spotted this pretty patterned toast optical illusion, I thought maybe, just maybe, I'll be better at it years later. Guess what? I'm not.
Can you see the hidden message?
{Image via Ooh, My Favorite}