I’ve found that being direct, but polite works well enough.

“Not to be rude, but I have to get this task done ASAP. Can we pick this up at another time? Thank you.”

1. You make every day brighter with your presence.
2. I love you.
3. Please don’t lick your junk within earshot. It sounds gross.

Making more frequent, smaller trips might make it less of a pain? Maybe stop by the dumpster if it’s on the way to/from a daily route you need to take?

Find the owner and tell them the cat is shitting on your property. If they tell you to pound sand, call city/county animal control to see what your options are. Alternatively, pick the shit up before your robot lawnmower runs it over.