This is what I look for in a pub, in no particular order:
Beer choice
Service
'Comfort'
In short, I ask myself the question, could I spend the afternoon here, by myself? If the answer is yes, then, to me, its a 'great' pub.
I can surprise myself. For example, my 'local' is the Queslett, a generic Ember in with up to 6 real ales on - yet I feel at home in there, where I don't usually feel like that in other Embers.
Soupy and I went on a crawl around Mere Green. We went into the Pint Pot which is an unspoilt 70s pub situated between an affluent area and a council estate. The residents of the estate use the Pint Pot while the 'well off' go to the Pubcos in and around Sutton. So in the 'Pot, we were surrounded by workmen in overalls and lads in tracksuits. There was only Old Speckled Hen as a real ale and Ansells Mild and Bitter on tap. Yet it was an incredibly warm and friendly pub. As 'great' as any other. I am not being condescending here, just contrasting the two pubs.
Yet the Anchor in Birmingham, a renowned real ale pub leaves me cold. I rarely use it.
I suppose how I feel about pubs comes down to just that - gut instinct.
Do others have some kind of formula, or is it just gut feeling that makes you want to stay in a place?