Dumbass Sayings: "When Life Gives You Lemons, Make Lemonade"
First off, why would life give you lemons? When does anyone ever come across a giant barrel of lemons randomly? It's a little difficult to put yourself in this hypothetical situation. Maybe instead say "If your uncle who owns a lemon farm bequeathed full ownership of it to you in his will and passed away yesterday, begin plans to construct a lemonade factory beside it." Then maybe I can better understand what you're trying to say.
Second, lemonade isn't THAT easy to make. You can't just squeeze lemons into a cup and sell that to people at the side of the road. I've tried that and they get really mad. In order to make lemonade you need things like sugar and water and other complicated ingredients. If you get to use extra ingredients then why not make a lemon meringue pie or lemon cookies or something? That would be better than just making lemonade. Maybe instead say "When life gives you lemons, make a whole bunch of assorted lemon related food and beverage products."
Third, making lemonade out of lemons isn't really the best thing you can do with a bunch of lemons. How many lemons are we talking about here? If life only gives you two lemons then most people would just walk away from that and not even give a crap, which doesn't fit with the whole idea of the saying. The lemons are meant to exemplify pain and bad situations so I would assume life is giving you several truck fulls of lemons. In this case the best thing to do would not be to make lemonade with them, but rather sell them to grocery stores or at a farmers market so you can get money for them. The saying should be "When life gives you lemons, ignore them, or if there's several thousand then arrange a deal with a farmers market to sell them."
The overall problem with the lemons saying is that lemons aren't inherently evil. Sure they're sour and no one really eats them raw, but they're not the worst thing you can get. People like to use this saying when it relates to real hardcore tragedies in life like cancer and death. Who would compare death with lemons? The more truthful, modern version of this saying would be "When life dumps a bucket of human shit on your head, make a viral video of it, then go take a shower and wash your hair with anti-bacterial shampoo." I've been saying this more and more to people and I think it sinks in a little better with people these days than the old fashioned lemon remark.