A Workplace Mistake

I once accidentally sent an email to my entire department instead of just one person. It was a routine update on the budget meeting I had scheduled, but with everyone's name in the To field and not BCC, it created quite a stir. People were confused at first, then started asking why they needed this information. My boss called me into his office to explain, and I just felt like an idiot. It was such a rookie mistake, yet here I am, in my 40s, making the same kind of blunder a fresh intern might make.