Which British small talk opener is the absolute gold standard?

A timeless opener that works in 11 months of the year and somehow still feels fresh. Bonus points if delivered while visibly shivering at a bus stop.

A greeting disguised as concern, requiring only a mumbled 'yeah, you?' in return. Answering honestly is considered a minor social crime.

Deployed at tills nationwide, usually while scanning a meal deal. Acceptable answers range from 'not too bad' to a deep sigh.

A safe harbour when all else fails, even if neither party actually watched it. Works at weddings, funerals and awkward lifts.

A bonding ritual based entirely on shared suffering on the M25 or a delayed Northern line. Instantly creates a fragile, beautiful camaraderie.