A maximizer is a person who always tries to make things as good as possible or get the most out of everything.
Being a maximizer can be good because it means you always try your best, but it can also be tiring because you never stop trying to make things better.
Examples:
She is a maximizer and always wants the best for everyone.
The maximizer tried to make the cake as big as possible.
The maximizer always wants more and more.
The maximizer even tries to make the sun shine brighter!
He's such a maximizer that he even tries to make the clouds whiter.
The maximizer never stops trying to make things better.