When Life Gives You C6H8O7

C6H8O7 is the organic compound citric acid, which is found in many citrus fruits (in this case, lemons). There is a popular adage that if life gives one lemons, it is best to make lemonade. In this joke, when life gives you C6H8O7 (citric acid/lemon juice), add H2O (water) and C12H22O11 (and table sugar/sucrose) to make lemonade.