The cat is offended  

By the spool of trimmer string
Left on the table after yardwork  

By the ballpoint pen
Left on the counter after writing a grocery list  

By the letter
Left on the doorside table after reading it  

Most of all by the thing that lurks behind him
Taunting, flicking
The thing that won’t be caught
Though he twirls until
He is dizzy and spent