It is something that is very difficult to put a finger on - a mix of possessions and people. I have been in houses/homes that are just not homey, even though those living in it are happy and content.
I think it may have something to do with how much the interior is a reflection of the family or how much it is a reflection of what someone thinks is the last fashion in decor.
My DM had the knack of making anywhere a home. My DF was in the forces and we were always on the move. Over 20 years about as many furnished hirings and furnished army quarters. Yet within days of moving into each one, my DM had made it clearly our home, no matter how dreadful the decor or ugly the furniture. She was so good at it other people used to comment on it.
The current estate agents/house sellers trend, at least, with more expensive homes, is to depersonalise them, by removing possessions and getting stylists in before the photos.
My neighbour's friendly comfortable homely18th century farmhouse, in the estate agents details, looks most off putting, more like a hotel than a home, the living room has pale carpets and a settee in it - and nothing else. Everything else has been cleared away and the bedroom seems to have nothing but a bed made up with the classic hotel throw across it.