Sometimes the most interesting conversations are the ones you're not even a part of. 

We've all done it — secretly staying on the line while our parents talk on the phone, subtly taking off your headphones to hear a fight on the train and glancing over at your friend's phone screen to see what they're texting their ex.  But sometimes, listening in on conversations can be a whole lot more interesting than catching some stray goss. 

To pregnancy confessions to cheaters caught in the act, here are the 20 most messed-up things people have overheard.