It is an interesting discussion.
Obviously we are all different and what is important to each of us will be different for each of us.
I don't know Cheltenham so can't comment specifically, but, having always had a garden, I think the thought of living without one would be SUCH a negative for me. I guess though, if you've never had one, it is more a case of not missing what you've never had.
I also think there can be both the element of being comfortable with what you are used to, but also an element of "the grass is always greener".
I love what I have - I live in a suburb of a big City. I still have a garden. I am close to loads of green spaces, from manicured parks to huge Country parks with hills and woods , to nature reserves, to smaller play areas, plus green corridors to walk or cycle through. I am also close to all the theatres, sports arenas, events, hospitals, exhibitions, specialist hospitals, you could imagine. Myriad of choice of where to eat (or get takeaways from) with competition keeping prices down. Shops (if that is your thing). A million and one things you, your small children, or your teens can join / belong to. Choices of schools. Choices of loads of different things so if you don't like one, you can try another. Be that a takeaway, a football team, a choir, a dance school, a cricket club, a theatre group, a Church or mosque or synagogue or Gurdwara, a Scout Group or cadets or guides or anything really. We have libraries and swimming baths and a plethora of supermarkets, and pubs or cafes etc etc etc etc.