What's the difference between using single and double quotes in strings? Is there a difference between using single-quoted and double-quoted strings?
There is a small difference, single-quoted strings don't support interpolation:

{% set string = 'There is a #{car}.' %}


The above example won't work. If you want to use it, you need to wrap your string in double quotes:

{% set string = "There is a #{car}." %}