don't take for granted

People tend to take for granted, especially things that is provided by our parent.
the simplest but clear and obvious example:
normally teen won't spent too much with their pocket money in things that their parent will buy for them. However, they are generous with things that their parent will not buy for them.
They will work hard to obtain what they desired but availalbe from their parent.
Why?

Please don't take for granted, it is not a compulsory for your parent to do so.
Appreciate what they did to us, your pocket money is their money too.

Ps: couldn't really express myself clearly....hope you guy understand.