Retrospective is one of the most important event during a Sprint.
Scrum opens up a quick feedback with the customer, but also, it opens up quickly a feedback loop within the Scrum team and the way they organize their work and collaboration.

Sometimes, weird stuff is proposed out of these retrospective sessions.

One common pitfall of retrospective for a Scrum team is noting all ideas without debating it. Not all ideas thrown during retrospectives are good ones. Ensure a majority agrees.