Does anyone have a good formula to manage difficult staff? ?

I would like to appreciate my staff but I feel tired nowadays doing so because they tend to go overboard. When you appreciate them in order to encourage them, by giving /treating them meals and gifts, they start to make it an obligation for the company to do so OFTEN because they feel that they (the staff) are 'important' ets and that the company needs to 'thank' them, and by saying this, my staff wants to be 'thanked' almost all the time. I feel that it is getting way out of hand. I really do not know what to do. My policy is to train people to be a better person for their own good and for the better of their families (cause most of the people I hire are from difficult backgrounds). At our company we make it a point that our staff become people that can contribute to the good of the society. But perhaps somewhere along the way I managed wrongly(so what should I be doing??!!) and instead I turned them into greedy people(greed for unnecessary benefits,greed for material and monetary gifts,etc etc) that think they are too smart for themselves. I am so disappointed. Will someone please tell me what should I do to handle the staff of a small retail business.