The example for "Friends don't let friends make heatmaps without maxing out outliers"[1] is so common. It's also very frequent in stats visualisations in videogames. If you play strategy or simulation games they often have visualisations to help the player understand what's going on/wrong, but for heatmaps because of the effect of outliers the heatmap gradient is often pretty useless. For example in the game oxygen not included, frequently if you do the temperature viz, everything just turns to either blue or some shade of pinky-red, because if you have a volcano or other heat source all the other colours seem cool. So you can't distinguish between a 1000C volcano and your slightly overheating 270C steam room for instance, they'll just be a pretty uniform shade of pinky red, and your overheating 60C base will be blue because it's pretty cold relative to them. Meaning that heatmap is pretty much useless for diagnosing a bunch of temperature problems.

[1] Can't remember the exact wording but that one it's like number 6 or 7.