Has someone ever given you an explanation that sounded so dumb that you wondered how dumb they thought you were? People are full of surprises, and the things that come from their mouths can be even more surprising.
When someone wants to convince you, they can give you all sorts of explanations. If someone sees the need to provide a rather long and complicated explanation, it's because of two things.
One is because they are lying, and two is because they are not good communicators. People feel the need to give more information if they are lying about something. This makes them feel like their story will be more convincing, and you'll accept it.
They may give long explanations about how they had to do something else, and that's why they couldn't make it. Long stories sound more convincing than short remarks.
An explanation about how their dog got hit by a car, the vet had to do emergency surgery, and they needed a recovery period of two weeks would sound more believable than ‘I was busy.'
If someone is somewhat antisocial and lacks good social or communication skills, they may have rather long explanations if they let you down. They may give you too much information trying to tell you why something happened the way it did.
If you constantly need to explain yourself, that's not right. Ask yourself why you feel that way. Do the people around you not trust you enough? Do you try to please people more than you should?
You are free to be yourself and do things without having to explain yourself. Self-confidence removes the need of having to convince others that you had to say and do this because of a particular reason. This collection of explanation quotes will inspire you to explain yourself less.