What tiny things have you done to specifically annoy someone?

[FlyingSoHigh]

My Mil came from a pretty wealthy family and definitely saw herself as a 'cut above' most people.
So I always used to chop carrots into rounds when she came for a meal as I knew she thought it was 'common'; posh people always cut carrots into sticks.
It was a tiny thing but it gave me so much pleasure over the years.
Can anyone beat passive-aggressive cooked carrots?

@sueelleker

You could have used a wash-out colour on your hair, then removed it before you saw her again.

Ha I never thought of that! but I did deliberately schedule a hair appointment to have my fringe cut in (was having it done anyway) after the morning school run. Thankfully she never copied that one!