It seems easier than ever to get out of a commitment at the last minute. The digital world has come to our aid - we are far less likely to feel the wrath of a disappointing voice on the end of the phone and our feeling of guilt feels less intense.
Even so, it's worth considering why we can't commit if we find we are cancelling on a regular basis. Often it is because we say yes too often; and probably weren't that interested n the first place.
Some people don't care. Others are simply too busy.
Sometimes we cancel and cannot discuss why; this can affect our relationships. People are apt to feel angry or rejected when the other person backs out. Our self esteem diminishes when other people cancel plans - we ask ourselves if the person is trustworthy, loyal and considerate - as we had assumed. People are more likely to forgive others if they rarely cancel plans or if they are in a long term relationship.
Perfectionist, narcissists and people who have trouble setting limits and expressing anger - often cancel plans. Perfectionists often find flimsy excuses to cancel social/business engagements. They want things to be as perfect; so they cancel. Narcissists tend to cancel plans because they put their own needs first. Perfectionists will mend their ways if it is pointed out, but narcissists won't because they are not empathetic.
Timid people often cancel because whilst they intend to keep their commitments by the time the date comes round they have got so much on they cancel. Other people cancel plans because they are angry but cannot express their hostility directly.
Discussing our issues with the other person can be helpful if we wish to avoid a rift which is important if we value our connections with others.