What are Rudy's 3 acts of stupidity?

I should preface this by saying Rudy is a bit of a rebel. What he does could have easily got himself and others killed. In that sense they can be seen as "stupid". Rudy. however, does them to stay true to who he is even at the risk of serious consequences. That being understood, you might consider,

1. Stealing the biggest potato from Mamer’s, the local grocer.

2. Taking on Franz Deutscher on Munich Street.

3. Skipping the Hitler Youth meetings altogether.

4. Jumping into a freezing river to fetch Liesel's book.