It has been a “season of regret,” with corporate miscues and apologies rampant: Toyota’s recall, NBC’s Jay Leno/ Conan O’Brien scheduling gaffe and final recognition of Time Warner’s AOL blunder. If only there were a do-over. What are the biggest mistakes in Jewish history? We asked Rabbi Charlie Buckholtz, senior editor at the Shalom Hartman Institute and author, to describe regrettable moments in Jewish history where a do-over might have been helpful. Tell us what you think. Any regrets on our regrets? E-mail us at email@example.com.