Mine are.

That a car will lurch forward slowly if you don’t have the break on, and is in gear.

That (a) and (an) determines if the next word starts with an (a,e,i,o,u) vowel, or a consonant.

Also

That when you are constipated sometimes pre-wiping with toilet paper helps.

Also that if you fart, then it might be a sign that you might poo soon.