Matthew 20:13 But he answered one of them and said, ‘Friend, I am doing you no wrong. Did you not agree with me for a denarius?
When you make a deal with someone do you try your very best to stick to that deal? How do you feel when you find out someone else has a better deal than you?
It is not nice to find out that someone else got more for their money than you, but we all make what we think are the best choices at the time given the best information.
When information and circumstance changes we should not expect others to bend over backward to make sure we get more for nothing!
Be happy with what you have managed to get; it is bound to be better than nothing!