It happens all the time; people have different ways of dealing with gratitude. As the religious song goes: ten men received help, but only one came back to give thanks. In the real world, this is very true.
There is a different concept about getting support. Others view it as an obligation on the part of the giver, especially if the latter is family. It may be true that charity begins at home; but a "thank you" or other grateful act acknowledging the deed is very much appreciated in the family.
When the help come from others who are not blood relation, the more gratefulness is expected. The problem may arise when the receiver has low emotional quotient - all he knows is he should get the help and when he is displeased all good deed will be erased. However, some may be receiving lesser help but everytime, a grateful act is given.
This is life. The lesson is: Do not expect anything in return when helping others. On the other hand, for those who receive help: Be grateful always - help does not come all the time.