Hey, did you think you were going to find out how Coulson came back from the dead right away? HAHAHA suckers, says Joss Whedon, more or less, as he messes with us in JJ Abrams-esque fashion...
"We can't wait to pull the curtain back on that," says co-creator Jed Whedon. "[But] we're going to take our time."
Just watch: they'll tease the "real" answer in the season finale, as a cliffhanger. You know it to be true. Then season 2 will ignore the issue for a while.
Entertainment Weekly has more Agents of SHIELD tidbits, including the fact that Coulson himself may not know how he returned.
Purgatory. He was in purgatory all along. Right?