Bias

Bias is the systematic favoring of one outcome over another.

If the scale used to weigh our watermelons is mis-calibrated, our measurements are biased favoring incorrect weights over correct ones.

If we notice that the last time we played Tesseract on our phones we got fewer coins than we're supposed to and say the game is rigged, we're biased in favor of the most recent play over the hundreds of other times we played and got the "right" amount of coins.

If we only look at returns of a stock on the first Monday of each month, we're biased by choosing some stupid way of looking at returns instead of looking at every day of the week, like we should.