Whenever I see a character in the anime, they typically have a color scheme I expect. However, there are a few examples where the coloring scheme is completely different than what I expect. This thread is about listing examples when a color scheme was different than how you imagined that character to be in color.
When I was a casual OP reader, only reading the manga from Shonen Jump, I originally thought Nami's hair was blonde instead of orange.
I imagined Oz as having a grayish blue or maybe grayish green skin color. When he appeared colored on the volumes, he was an orange color, which was a bit surprising, but not too much of a shock. But when he appeared red in the anime, it was completely different than I thought it would be.
On the other hand, I imagined Kuma as having the anime's coloring scheme, and the manga's (with the orange vest) still seems awkward to me.