Monkey Waiters & Optical Illusions

How this works:
Just keep focusing on the dot in the middle of the castle until the end of the video. That's it! Do you know what the illusion is? If you don't get the illusion (and chances are you didn't), watch it again, but this time, without looking at the dot.
Get it now? For those who still can't get it, answer click below.

So what was the illusion? The second picture was grey the entire time and your mind just put all those colors there!! Try again!