I grew up with plenty of Humility and Respect for people but suddenly realize I will rather give excuse than tell someone am sorry.
Its common these especially among men. I feel the height today when my sister remainded me that I didn't call her on her birthday...instead of apologizing I put up excuses.
I want to know why and give us insight on how to correct it.

It's just unnecesary ego and pride.
One of my favourite portions of the bible is the part that says to prefer one another in love..., really, if you don't think you're the bestest and rightest, saying sorry ain't that difficult.