Do not promise anything. A suprise is better than a promise fulfilled by force.
If you have no promises, and you just save little by little just to please your children or your father,it will be very, very pleasing to them to receive a gift which they do not expect, other than receive a promise which they know is very hard to get, which they know and they are aware that you are to suffer just to keep every promises. You see, it is just like in dealing with God, God does not want us to take a vow which cannot be done by us as we have said it, the bible tells us in the book of Ecclesiastes 5:4 it says, when thou vowest a vow unto God, defer not to pay it; for he hath no pleasure in fools; pay that which thou hast vowed.
Verse 5, better is it that thou shouldest bot vow, than thou shouldest vow and not pay.
It is just like promising something which will entail a long time for that promise to be fulfilled. You see, while they are waiting for your promise, their heart aches.
Proverbs 13 verse 12 says, hope deferred maketh the heart sick,but when the desire cometh it is a tree of life.
It will even pain the heart when the hope is being deferred.
When the promise is not fulfilled at once,there is a longing there that may pain the heart. But you see when the desire cometh, it is a tree of life. So, a desire fulfilled is joy.