General annoyance:
* Those pesky mosquitoes kept me awake all night.
* The pesky neighbor's dog barks all day long.
Specific annoyances:
* I finally fixed that pesky leak in the kitchen sink.
* I can't seem to get rid of this pesky cough.
Humorous:
* My pesky little brother keeps asking me to play video games.
* That pesky feeling of unfinished business just won't go away.
Figurative:
* The pesky rumors about the company's financial troubles are starting to spread.
* Those pesky deadlines keep me busy.