Sorry, I can't....

We have all been in that situation where we really don't want to do something, but instead of flat out saying no we just comply or make up some excuse. Well, on wed night this exact thing happened to me! It was roomates birthday and we all went to dinner at Cheddars. Afterwards they were all going out to the bars downtown, but I just really didn't feel like attending! My roomate said "Hey do you wanna come downtown with us". Unconciously I said "Aww I can't I have a test tomorrow". I flat out lied to her! I felt bad at the time.... but I shouldn't have because I was just using a linguistic concept! (I tell myself this to make myself feel better about lying ha) She offered/invited me and I used the dispreferred second by refusing the offer. It would have been easier to just say no, but then that wouldn't have been very polite. Instead I had to make up a lie or in other words (flouting the maxim of quality). I've realized that these situations come up almost everyday and in every situation I always use some sort of flouting or second preference! At least now I don't feel bad since I know there is an actual term for it!