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
Jessamine	JES-ə-min	English (Rare)
Mahmoud	-	Arabic, Persian
Whetu	-	Maori
Partha	-	Hinduism, Bengali, Indian, Assamese
Amittai	ə-MIT-ie (English)	Biblical
Vega	['vi:gə]