ride (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 starts riding his hobby-horse about the government, there's no stopping him!

Common Names:

Name	Pronounced	Usage
Ernest	UR-nəst (English)	English, French, Slovene, Polish
Richa	-	Indian, Hindi, Marathi, Malayalam, Bengali
Jennica	JEN-i-kə	English (Rare)
ThorbjÖRn	-	Swedish
Jengo	-	Eastern African, Swahili
Hillman	['hilmən]