Imagine this situation: you are walking along a busy street when a man near you gets ill. Will you help him or will you decide that there are enough other people around to provide help? Alas, the latter option is more likely to happen. And not because you are a "bad person", but becausethe bystander effect is at play.
How many senses does a person have? Vision, hearing, taste, olfaction, and haptic perception...that makes five. The sixth sense is usually considered the ability to foresee the future. But is there anything that we forgot?