Bosnian, like English, makes a distinction between "good evening" and "good night." "Good evening" is a greeting, but you would only say "good night" as you are leaving someone late at night or going to sleep.
I was trying to teach Isaac the phrase for "good night"--"laku noć." "I already know that, Mom," he told me. "I said it to the girl I sit next to at school."
"Why would you say that to her in the afternoon at school?"
"I said, 'Laku noć,' and then I put my head down and my desk and started snoring, and she laughed."