“[After the doorbell rings, right before Secretariat appears] Who's that at the door?!”
citation needed
The Late Late Show with Craig Ferguson (2005–2014), Commonly repeated
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Craig Ferguson 118
Scottish-born American television host, stand-up comedian, … 1962Related quotes

“The more Susan waited, the more the doorbell didn't ring. Or the phone.”
Source: Dirk Gently's Holistic Detective Agency

“Democracy means that if the doorbell rings in the early hours, it is likely to be the milkman.”
Widely quoted and attributed, but without a documented source.
Disputed
“I’m the candidate who forgot to take off her hat before she threw it in the ring.”
Source: How to Become President (1940), Ch. 4 : How to attract attention and be drafted
Context: You remember me. I’m Gracie Allen. I’m the candidate who forgot to take off her hat before she threw it in the ring.
Furthermore, I’m the only candidate who got the idea of running myself. All the others had to have somebody else think it up for them, or anyway they say the only reason they’re running is because their many friends kept after them and after them until they finally gave in.

2020
Source: Address to the Nation on Coronavirus pandemic on 19 March 2020 https://www.indiatoday.in/india/story/pm-modi-speech-on-coronavirus-thank-corona-warriors-1657591-2020-03-19

“Bright is the ring of words
When the right man rings them.”
No. XIV
Songs of Travel and Other Verses (1896)

“Opportunity only knocks once, but temptation leans on the doorbell.”
Attributed quotes