Hydrangeas make me happy

I had a grumpy moment yesterday and the hydrangeas cheered me up. My parents have a Summer rental at the shore. Most rentals are handled by the realtor, but some my Dad does himself. They are mostly friends-of-friends and he never makes the people pay up front, he lets them pay the day their rental starts (I know, but it's his house, so it's his way)
Anyway, I clean between tenants on Saturdays and I spend the weekend in the efficency cottage out back. The people renting the house this week have been renting for a few years and they know that I'm staying out back and that they are supposed to pay me. Do they bring the rent money out to me? No.
So Sunday before I leave, I go knocking on the door to get the rent. I'm feeling grumpy, because I shouldn't have to chase these people down for the rent. No one answers the door - but I can hear the tv! I knock and knock, but no one comes to the door. So I go stomping down the porch steps bitching and complaining in my head, and I pass the garden. That's when I catch sight of my pretty, pretty hydrangeas. Instant cheer. So I cut some to bring home with me, and put them in a pretty vase on my desk.
These are my favorite colors for hydrangeas - pale lavender, blue and green, I love the varying shades.



I'm going back tonight for the rent. All day I've been trying to figure out how to let them know that I'm pissed, without being rude.

***Update - the rent has been paid, and I was very polite.