In English and most European languages, people read and write from left to right. This is why left alignment or "flush left" is one of the most common alignments on the web. It feels natural, mimicking the flow of our eyes, and guarantees better readability for large pieces of writing.

This rule doesn't apply to right-to-left languages, such as Arabic, Hebrew, Persian, or Urdu. In those cases, right-aligned (flush right) text is more readable.^[1]