My reasons...

Hills. I love that Luton is surrounded by hills - you're never far from somewhere you can escape. Plus, I love heights and looking down on things from a different perspective - I miss being able to sit up high, and just watch the world continue.

Community. I suppose most have this in their town, however it seems a little different in Luton. Most people I talk to don't have the same background of friendships and people they know. *shrugs* That's just personal opinion.

Green spaces. There seem so many! Wardown, Stockwood, Wigmore, Stopsley, Pope's Meadow, and many more. Good memories of relaxing in parks with various people. Also, being taken to various playgrounds when little :)

As Tim said, it's not that I don't see its bad bits - they just don't affect my opinions. Instead, I love it more for its shining moments.