LOL! 20,000 is large compared to the small towns I've lived in. The town I grew up in was around 8,000 ( not much larger today) and the town I've lived in for the past 21 years is around the same size population wise.
I love it. People here are friendly but not in your business. If you need help they are there without having to ask. Just recently a dairy farmer dropped off some wonderful sugar and gold corn for us to enjoy and had his son drop off a round bale of hay for my horses. Just because, no other reason. If we need fertilizer for the garden, he'll drop off a tractor bucket load.
I love running to the general store and bump into neighbors and friends. Most times we only wave to each other in passing on the road, since we're all very busy running to work or whatever place we need to be.
When my children were young I enjoyed volunteering at the schools when I could get time off from work. Got to know the teachers and other parents/children.
There is a deep sense of family and community pride here. People always volunteer to help with whatever needs to be done in the town. And have a ball doing so (who says you can't have fun and work at the same time).
Of course the down side is , do something stupid and people will remember it for ever. But then I figure I'm good for entertainment so who cares!