They say when you laugh, your life lasts, but no one knows the truth of it or not, every person laughs day by day, sometimes even for different trifles. People laugh when they express their joy, sometimes laughter can be just a mockery. When some people laugh at others it's called a ridicule "Of course it's a bad laugh, when someone laughs at you, it's horrible and humiliating." I think that you should laugh only when you're really funny, do not laugh from other people when at this time it's bad, because then they'll laugh at you, and you'll be able to feel how it's "nice". For me, laughter is life.