Until youare confronted with this possible disconnect, pardon the pun, not in good taste. The real answer might be, well, i was afraid i wouldn't do a good job. Your brain doesn't want to say that and so it says something like 'i had too many other things to do' Instead of saying what is true, blurts out something that feels good,. sounds good, and often convinces the other people and they leave you alone. So your then get into the habit of using this, this excuse, and you're not aware of it exactly.