On top of these items, perhaps the oxygen to the heart if you will, is less of a focus on price competition which has hurt gross margin.

FORBES: Wal-Mart Shows A Pulse And It's Thumping

This is why airlines ask you to put on your oxygen mask first.

FORBES: 10 Surprising Assertions From Elite Entrepreneurs

The reduced oxygen levels will take their toll during the time aloft, and the net result is that tired, lethargic feeling when you land.

FORBES: Flying in Rarified Air: Gulfstream's Amazing G650