We all know that phrases like “How's it going?” and “How are you?” are mostly pleasantries.
It's just how we say "Hello." You're not expected to answer any more than the person asking is expected to care.
But every once in a while, someone will surprise you. You'll toss out a casual and totally insincere “How are you?” and the floodgates will open out of nowhere. “I've had the WORST DAY,” they'll say.