Before Nong Bua had an office I used Udon Thani also. Same as you, I was treated nicely and they sometimes filled out paperwork as well. Generally Thai govt officials do as they are treated. Respect earns respect
Sorry to hear that. Here in Nong Bua Lam Phu it's quite the opposite. They are always very pleasant and beyond helpful. Sometimes they even fill out the paper work and point to where to sign.