A banality is a trite, boring, or overused remark. That includes clichés like "life is short" and your basic small talk about the weather.
Banalities are sayings that almost everyone uses, and because they're so well-known, they've lost all they're power. These expressions are clichéd and many people find them annoying. "When life hands you lemons, make lemonade" is one good example. When you're writing or speaking, you're much better off trying to find fresh language because one needs to hear the same old banalities again and again.
