get on (one's) hobby-horse

To frequently or incessantly talk or complain about a subject, topic, or issue in which one is excessively interested. Ah, here we go again. Once grandpa gets on his hobby-horse about the government, there's no stopping him!

Common Names:

Name	Pronounced	Usage
Armida	-	Italian, Spanish
Evgeny	yev-GYE-nee, eev-GYE-nee	Russian
Caitlyn	KAYT-lin	English (Modern)
Frederick	['fredrik]
Gayelord	GAY-lord	English (Rare)
Christin	kris-TEEN (Swedish, German)	Swedish, Norwegian, Danish, German