How true do u find this to be? I once heard the same things that can make you laugh can make you cry and vice?

I am familiar with a quote saying something about somethin that made you laugh once, will make you cry. Perhaps, experiencing enough negativity led them to find humour in life. They wanted to brighten the mood. Some people take life more seriously than others. i think they mask their pain through humor. they probably like to make others happy.