Simplicity bias/Occam's razor
Occam's razor is often mis-paraphrased as "the simplest explanation is usually best" – but this itself is an oversimplification. What the razor actually says is that when multiple satisfactory explanations are possible, the one with the fewest assumptions should be selected. It is understood that these assumptions must actually explain the available evidence, or at least be consistent with it. The "moral" behind the razor is generally taken to be that one shouldn't unnecessarily complicate an explanation – or, in other words, it is advocacy against what might be called "complexity bias", a tendency to add elaborations to a simple but sufficient hypothesis.
Simplicity bias operates in the other direction – people tend to prefer explanations simple enough to understand easily, even when those explanations don't actually satisfy the available evidence. Simplicity bias causes one to overlook data that doesn't fit one's preferred explanation.