Effect called when humans overvalue one good event after series of Bad events and Overexaggeration one single bad event after series of Good events

Solution 1:

Overvaluing the last (most recent) effect is recency bias.

Wikipedia: Recency bias is a cognitive bias that favors recent events over historic ones. (https://en.wikipedia.org/wiki/Recency_bias)

Solution 2:

This is called the contrast effect.

From Wikipedia:

A contrast effect is the enhancement or diminishment, relative to normal, of perception, cognition or related performance as a result of successive (immediately previous) or simultaneous exposure to a stimulus of lesser or greater value in the same dimension.