“Thanks” Costs Nought

People who have poor manners drive me nuts, but I’m too polite to say to them that they are being impolite, for that would be impolite. If someone were to hold a lift, open a door or let me jump the queue if I only have a couple of items to check, then the least I would do is say a gracious “thank you”. Surely it isn’t too much to ask of society that the same can be expected when I offer a similar civility? Good manners cost not a bean; if they did cost a bean I’d buy a great big sack and hand them out to ensure politeness abounded.