A positive outlook

A bit of folk philosophy:

When life gives you lemons,

make lemonade.

In other words, when faced with a setback or difficulty, try to turn it into something positive. Turn the sour (lemons) into the sweet (lemonade).

[NB: In AmEng, lemonade refers to a beverage made with lemons, sugar and water. In BrEng, it means a carbonated beverage like Sprite, Fanta Lemon or 7-Up.]

Other common optimistic expressions:

Always look on the bright side of life. This expression was made super famous by a song of the same name which appeared in the Monty Python film, The Life of Brian.

Every cloud has a silver lining - a very similar expression to the first one.