When given a choice between getting $1,000 with certainty, or having a 50% chance of getting $2,500, most people will choose the certain $1,000 — even though the expected value (the average value over repeated trials) of the uncertain option is $1,250. Most people would reject a gamble where they would gain $100 if a fair coin lands on heads, and lose $100 when the coin lands on tails, because losses have a much higher impact than gains.