People have, do, and will disappoint you.
Simple fact of life.
Ask yourself two questions: did they intend to do damage, and what are you going to do with the disappointment?
Let's look at the first question. People are deeply involved in their own lives. That doesn't mean they don't care about you or others, but they are first motivated to deal with their own situations and personal emotions. The more mature, considerate, and less self-centered will also shift gears back and forth to consider the consequences of their actions or inactions.
Personality styles, however, are consistent. Those who shun confrontation because they don't want shrapnel of any kind aimed at them will probably
stand up for you, watch your back, defend you or come to your aid during that particular moment of need. That's who they are. They might gossip to you later about it, tell you "tsk, tsk, tsk" this happened to you, or just ignore it completely like it never happened.
These people will disappoint you often
if you maintain the irrational hope that they will change some day and be there for you in a big way. As I've said many times, most hope is simply postponed disappointment.
So your disappointments mostly do not come from ill intent. They generally come from individuals whose number you now have, and this is when we get to the second question: what do you do with your disappointment?
Personally, I have told several people over the years I was disappointed I couldn't count on them to stand up for me when I thought it counted. Some of these folks loved me dearly but just didn't have it in them to become a target or focus of that kind of attention. Some people simply are weak and frightened, although they're basically decent. I put these people in a more distant circle of love and affection, but they are still there at all, because I know they care. They're just supremely limited. Others who have disappointed me have been relegated to the back of my mind, and I am just polite to them. Still others - well, they become invisible, especially if I have put myself out for them when it mattered for and to them.
The people willing to put themselves in the line of fire for your friendship or your principles are the people to embrace the closest in spite of any other quirks that might annoy you at times. People who will watch your back and/or stand in front to shield you are special people.
Special people should not be taken lightly. They should be cherished and rewarded with your affection and respect. It is not typical in the animal kingdom for critters necessarily to put themselves in harm's way to protect another. It takes a special form of human being with moral choice to do that.
are our everyday heroes.