Break the ice
(idiom)
Meaning: To do or say something to relieve tension or get a conversation started, especially with strangers.
Example: He told a joke to break the ice at the start of the meeting.
Hit the nail on the head
(idiom)
Meaning: To describe exactly what is causing a situation or problem; to be exactly right.
Example: You hit the nail on the head when you said the delay was due to poor planning.
Once in a blue moon
(idiom)
Meaning: Very rarely; almost never.
Example: We used to meet every week, but now we only catch up once in a blue moon.