Some days could just be filled with disappointments,I feel bad,I feel terrible but then it's part of what we see in our daily lives....
People would always disappoint,we are all humans but then we need patience to be able to accommodate other people's excesses and also be calm.
Imagine disappointing someone, expecting him or her to yell and afterwards the person just talk to you calmly and find an alternative.
Life must not always go the way we want, rather than flaring up,you could find a solution or prevent things from getting bad.