According to the Dog Days Are Over Songfacts, this paean to the inevitability of happiness was inspired by a giant text installation titled "Dog Days Are Over" by artist Ugo Rondinone, which Florence used to see every day riding her bike over Waterloo Bridge.
Happiness, hit her like a train on a track
Coming towards her, stuck still no turning back
She hid around corners and she hid under beds
She killed it with kisses and from it she fled