In some areas, superstitions persist because scientific research isn't doing all that much to dispell them. The science is controversial and available evidence isn't straightforward. Consider how many people think about nutrition and diets. Often people choose what to eat based on invisible attributes associated with food (labelling) that we as consumers can't observe directly.

Opaque processes can do it too. With the rise of targeted advertising, coincidences can easily be interpreted as the result of someone watching you whether they are or not.