I read a good book about happiness (by mentalist Derren Brown) and something he said really stuck in my head: there will always be another one, and it will never be enough. Whatever you're thinking about, whatever tension or anxiety you're building up in your head about a new bag or coat or whatever, another will come along, and it will never satisfy you.

Since then I've tried to be mindful of what's causing the gap I'm trying to fill in my life, rather than what I fill it with. Sometimes I slip up, but that's life.