pigletmania I am not specifically talking about money for lifts (trying to figure where I am telling receivers of lifts how to thanks me) I am talking about in general, when it comes to paying a share and how some people get it so wrong.
A few years back a dear friend moved to England from Scotland and came to stay with us as her partner was running the Glasgow marathon. They called from the airport to ask if his colleague who was also running could crash at ours too. We only had one spare room but he was happy with the sofa. Dh picked them up at the airport, I got the brunch ready. We all went out for a bit, came home and I made dinner, supplied all wine/beers. Next day, marathon day, I made a huge breakfast. After the marathon they came back to hot baths and beers. I made a Sunday roast. The following day I couldn't face cooking and ordered chinese delivery. As it arrived, friends partner stands at the living room door, a long hall from the front door, and asks dh if you want any money toward that 
Just what kind of offer is that? It's no offer, its grudged, its mean and its insulting. The decent thing is to insist on paying it, to walk up and hand the delivery driver the money. Instead he put dh in the position of having to say yes or no, and that is rude. Dh said nah, your fine. Friends partner was delighted and opened another beer. As we were driving them to the airport the next morning, he asked to stop at the petrol station. Came back to the car with a small bunch of forecourt flowers with the red reduced to two pound# sticker on.
That was his appreciation for all we did.
Mean, and they call the Scots mean.
If an offer of thanks isn't genuinely meant, its best left unsaid.