I had the great pleasure of interning in Senator X's office, but once committed an error of such internish stupidity that I feel it must be shared. One day towards the middle of my internship, Senator X's spouse stopped by the office while Senator X was still out at a hearing or something of that nature. The senior staff were on good terms with the spouse, and they chatted in the office. Because one of the staffers was sitting at their desk, those outside her office were talking fairly loudly so that she could hear. This meant that I could also hear the conversation.
At some point, Senator X's spouse asked about the time of an event going on on the Hill that day. Being the earnest intern I was, I immediately piped up with the details, blissfully unaware of the multiple mistakes I was making. I had also revealed that A: I wasn't focused on my current task; B: I was listening in on a conversation that didn't involve me; and C: that I was egotistical enough to interrupt said conversation.
Looking back on it, I'm amazed that the staffer who corrected me afterward wasn't more harsh.