Disappointment is one of the worst feelings I can experience. It usually stems from high expectations and broken promises. A promise can be defined as a declaration assuring that a person will or will not do something, to afford a basis for expectation, or just a hint that something favourable may come.
I always make promises to myself to remind myself to do certain things. It's a way of setting the bar higher, and if I fail to meet my own promises, I let myself down. When someone promises me something, I expect them to follow through. If they fail to deliver, I will definitely be disappointed. I've learned that people can and will let you down. Some take my trust for granted and make empty promises just to shut me up, or they make promises as a form of trading. All of my ex-boyfriends promised that they'd love me forever; I guess that promise had an expiry date I wasn't aware of.
Many of us make promises to God to act in certain ways if He'll grant our requests. Do you realise these promises are often driven by selfish motives, rather than a desire to please God or improve ourselves? It's tough to be good all the time and to make unselfish prayers, but if these wishes are driven by genuine purposes, God has promised He will answer them, and His promises are never broken.