Sometimes, I try so hard to be a people pleaser and avoid disapointing my children. However, I know it's impossible to please everyone all the time. So this hard truth about disappointment is an inevitable reality.
I think what is most important is how we deal with the disappointments of life. Does it change our attitude? Does it drastically alter our emotion? Does it send us into depression? ...How one handles disappointment is a good indication of their level of maturity and willingness to grow and learn.
Consider examining your most recent disappointment and how you handled the situation. Does it still have a grip on your emotions?