What is wrong so I may improve it?
This is sort of a hard thing to explain, but I'll just go ahead and say that overall the build quality just isn't good enough.
The building has no windows and it is incredibly bland. There's just not enough style to the building itself or none at all. It doesn't give off a vibe, it's literally just a box. Most of the interior is pretty mediocre and could be improved. I suggest you to think about what kind of bar you're aiming to make and then recreate it, such as if it were an old western saloon, or something more modern.
Those are just my tips, but if you need to know how to build quality then you're gonna have to work on that on your own.