"The truth. It is a beautiful and terrible thing, and should therefore be treated with great caution." Dumbledore, in Harry Potter series by J.K Rowling.
Lying is an everyday habit, I believe. All of us are guilty of that, no? Thing is, lies vary, depending on the motivation, and the results. Our reaction should not be the same all the time.
Small as 'I've got the Mail already', when you are in fact on your way to get them? (Here, I guess you are trying to avoid a confrontation, especially when you have been reminded several times) So, the problem is not lying, more of your procrastinating habits.
Big as 'I'm not married' Obvious enough that there's no way around that this is a very unforgivable lie.
Personally, I prefer to hide the truth, or answer vaguely, rather than outright lie. Some people would call that lying anyway.
Not lying at all? Good luck being able to do that.
So, if you are forced to lie sometimes, you should not be so quick to shun those people, or make them feel like a heel, especially if they apologize.
A quick answer?
If you care deeply about the offender, then you should confront them, and encourage them to be more honest with you. Otherwise, don't bother. If you confront every lie you discover, you'll never finish!