I live very near this place and so it should have become my local - a go-to spot for excellent coffee and to sit reading the papers. In reality, I very rarely go there except to pick up a takeaway. The coffee is extremely good, but as others have noted, they simply can't seem to be bothered with friendly service. I've never experienced outright rudeness, but I've never got a single smile, or a bit of banter, or a 'How are you today?'. Nope. Nothing. And that sets the tone of the entire place. If you don't feel welcomed, if your custom doesn't seem to be valued, you're not inclined to spend more time there. Or more money.
Compare and contrast with the absolutely tiny Goodge St Espresso, a five-minute walk away. You can't sit down there, and it's no more than a hole in the wall with a single barista, but the coffee is fantastic and the owner is absolutely lovely. The second time I popped in there, he recognised me instantly and said 'Flat white again?'. He remembers who you are and what you drink, and he greets customers with genuine warmth and interest. That's what people respond to, Store St Espresso. Try smiling at your customers a little bit and see how the atmosphere changes - and how many locals like me actually come back to spend their money.