Have you ever gone to an interview and felt surely that you nailed it? After days of waiting by the phone, you get no reply or a reply that another candidate has been chosen. Did you ever wonder what happened? You dressed the part. Sat up straight. Made good eye contact and you were surely knowledgeable. Well, sometimes it was something that you didn't expect that turned a win into a lose.
Did you mention that you went hunting over the weekend? Did you mention that you were almost late because you didn't have a babysitter? These subtle and innocent comments can be used against and you don't even know it. Information that we share will tell a hiring person things that can be used to pass on you as a hired candidate.
What if the person hiring is strongly against guns for hunting? Could your not having a babysitter available when you have a scheduled interview send a message that you do not manage your time well or prepare for things in a timely manner? These events in and of themselves are really no big deal right? To a hiring manager, the person who is looking to bring someone into the team that will be compatible with the company's culture and beliefs, you could have alienated yourself without knowing.
So. the moral from this story is to "keep information that you share honest but generic." Don't give anyone anything to discriminate against. This isn't as tricky as it sounds. Just be pleasant and exchange basic pleasantries. No need to open up your personal hobbies or about struggles or challenges in your household. Use the interview as a time to show your best you.