Should we ignore risk?

Every day we face all sorts of risk that we could be hit by a car or even choke to death when drinking water. However, these extreme cases only happen with very small probabilities. Within our economy, extreme cases do exist. Should we ignore these extreme cases? It depends on the expected return of ignoring the risk and the expected return of taking actions to hedge against the risk. It the expected return of ignoring the risk is higher, then feel free to ignore the risk, and vice versa. Moreover, we could not expect ourselves to know all the existing risk. The most obvious risk usually has the highest probability and the least obvious risk has the lowest probability. When the probability is small enough, it is ok to ignore it without having signficant impacts on the estimates.