Choose the verb mitigate when something lessens the unpleasantness of a situation. You can mitigate your parents' anger by telling them you were late to dinner because you were helping your elderly neighbor.
The somewhat formal verb mitigate comes from the Latin roots mītis "soft" and agere "to do/act," which add up to "to soften." It is often used with words that indicate an outcome or something harmful. When you buy car insurance, you are trying to mitigate the risks involved with driving. Sunscreen is used to mitigate the effects of the sun on your skin.