Take one bridge.
Add one tall man and one short woman who are definitely not interested in each other.
Combine using a generous prod from an interfering friend who thinks he knows better.
Excise interfering friend and leave to brew for approximately six hours until the sun has gone down.
Remove from the bridge and relocate to the pub.
Leave to develop for another three hours.
Separate man from woman.
Pretend to ignore the situation for two weeks while secretly looking at it every few minutes.
Reunite man and woman in a dark space, accompanied by popcorn and the anniversary re-release of a bloody good film.
Admit that the interfering friend may have had a good point.