I take every quiz, but I only take it once and live with whatever score I get.
I don't see the point of achieving 100% via multiple attempts, because it's not really much of an achievement when you already know the answers.
The same can be said for people who get 100% but take so long it's obvious they looked up the answers, or people who get 100% in their first time in less time than it takes to read each question, because it's obvious they had a practice run with an alternative account, then took the test on their main account and hit the correct answer as quickly as possible.
The top scores in these quizzes are a battle of reaction times and internet connections.