Stopped for diesel at a fuel station on the 121 Hang Dong area and asked for 500 bahts worth. Whilst that was in progress the wife noticed some mangosteen on the adjacent pump island and asked to buy some, the pump attendant said sorry, it's free with 700 baht worth of fuel, no problem says wife.
Another attendant, senior I guess, had overheard the conversation and as we were about to leave tapped on the window, and with a big smile gave my wife a bag of mangosteen, pointed to the badge on her shirt and said PT care!
A nice touch.