No parent set out to have spoiled kids. We give them the best because we simply want them to be happy. However, blindly giving children everything they want may cultivate a sense of entitlement in them - they stop appreciating what they have and expect to always be given what they want.
According to child discipline experts, it is behaviour, and not possessions, that defines a child being spoiled. Pampering children with presents, for example, does not necessarily spoil them, but giving them something as tiny as a piece of chocolate just because a child demands it does.
Parents have a huge part to play in this. Giving in to tantrums, especially public ones, teaches children that they can get what they want as long as they are loud enough. Bribing them with toys or ice-cream into compliance develops an attachment for external rewards over internal values. Picking up after them, because it's easier than getting them to do it themselves, prevents them from learning about being responsible and accountable. When made into a norm, these can give children an unrealistic expectation not only from their parents, but from other people they meet growing up.
Instead of taking the easy way out, making the effort to be firm and consistent with children is far better for them in the long run. Lifelong lessons, such as coping with disappointment and showing empathy, can be learnt in daily moments when parents stand their ground, explain things to them, and let them work for what they want as opposed to caving in just to avoid dealing with a potential meltdown or shielding them from difficult emotions.
After all, more than stopping whining or tantrums, we are looking to raise happy and resilient children, ready to take on a world that doesn't necessarily satisfy their every whim.