Surely this sign should read: 'Unhappiness? try a Therapy' Neal's Yard Remedies are selling remedies for unhappiness, they are selling short term happiness, happiness as a feeling, which allows us to temporarily escape from life's bigger problems.
That's fine, but it is a sad state of affairs. Stepping back out onto the busy pavement with your bag full of therapy and your reciept for a 'holisitic massage' weighing you down is just like when you get home after a shopping spree, an exotic holiday, or a big night out on the tiles, a sudden realisation hits you that, 'shit, all those problems are still there just waiting for me.'
Treat yourself: Get off the hedonic treadmill, find wellbeing through well doing!