Often get a thank you off folk as a guard when I'm on the platform, seems less common for drivers to get a thank you unless theyre standing by the cab door on arrival at the terminus - I have thanked the driver myself in the past - My old local station has the exit steps at the front of the train, you'd often get most people thanking the driver as they walked past if their window was open.
Not quite the same, but I was waiting late one night for a freight working to pass through. The last service of the night rolled up and the driver stopped next to me. He asked what I was up to etc - bit odd to lurk at a quiet station and miss the last train, told him what I was waiting for, and he replied with "I saw it on the way down, its waiting at Dee Marsh until we have cleared the section and the possession can commence".
I'm not one to talk to drivers about spotting etc, but thought itd be better to tell him why I'm there than have BTP phoned or something!