Raising your hand with a question everyone else is too scared to ask is a public service.

Confusion in a classroom is almost always shared. Thirty people are in roughly the same state, each one privately concluding they are the single person who lost the thread, and every silent face confirms that conclusion for everybody else. One hand breaks the arrangement and resolves the same gap for a whole room at once, which is why it counts as more than a favour to yourself.

Ask the next time you are lost rather than waiting to see if it clears. Then look around while the answer is being given.