I've noticed my MBA 13 does not sit flat, i.e., the "lower" left rubber foot doesn't touch the table. Whenever I type the foot taps on the surface. Drives me crazy. I brought it to the Apple Store for an unrelated issue and mentioned the problem. The Genius ran my serial and told me because I bought it more than a month ago (~Dec 23, 2013), he could do nothing about it because the "damage" was likely my fault. Is there anything else I can do? It seems like this is a common problem with the MBA.