Relax and stare at this image for a while. After said while (thirty seconds…ish), the colours will begin to disappear (no it’s not a gif). You can even make them go away completely.
What’s happening is called Troxler’s Fading. After a while of receiving the same non-changing information, your brain gets bored and just discards the information because it’s too busy keeping an eye out for more pressing, changing information, like tiger attacks.
You know how when you wear a watch for a while you stop noticing it. Same thing. Your brain is an idiot.