How is life a box of chocolates? Everyone loves chocolate. You can say you get a bit of everything, but like, if you like ALL chocolate that means everyday would be a good day, right? Like, unless your a sociopath that loves death and destruction, not everyday is going to be good. Wait sociopaths have bad days too, because sometimes their plans get screwed and they get mad. Even sociopaths have bad days! So how is life a box of chocolates?! Next metaphor, Life is a rollercoaster, it goes up and down. Ok, if your life is like perfect one day, and then just suddenly takes a flop for like twenty days, and then suddenly everything is crazy and then good again, that's an odd life schedule. Life could sorta be like one of those kiddy coasters. People who are depressed would have life be like a rollercoaster that is forever going down.
If I were to say that life is like anything, life is like a slowly degrading man, who then suddenly is a billionaire. In other words, life is random.