a few more things to consider in response to various notes:
it is normal to want things and normal to not be happy when you can't have them. neither is a moral failing and if you think it is you better be living like a cave monk.
while learning to deal with disappointment is an important emotional skill, research has yet to deduce the relationship between this fact and the way parents act like they are heroically throwing themselves on grenades for the benefit of humanity because they could have bought ice cream but decided not to.
most children are, in fact, capable of understanding the difference between "material circumstances make this impossible" and "authority figure arbitrarily said no", and do not necessarily learn from the latter how to deal with the former.
it is true, as a few people have noted in tags, that some parents hurt their kids by trying to make up for emotional absence with material gifts. if your concern about this is genuine you can probably recognise that insulting the child is not the best response.
if you want to see someone who "can't handle being told no", try watching a parent whose child has just said no to them.