Okay, this is a generally easy challenge, I figure. All you have to do is create two characters.
One has to have an otherwise desireable trait(e.g. optimism) to the extent to where it is annoying. The other can either be very annoyed by it and complain often, or slighty annoyed by it and never bring it up. Or something inbetween. Just make them notice it.
I will judge this on my birthday. Why? Because it’s a significant date.