I was sitting outsdie the Los Altos Starbucks, enjoying an Iced Late, when suddnly I hear a Pffffsssst!, and my front tire goes flat right in front of me..... The bike was just leaning against the wall!!! took 3-4 seconds for it to go totally flat.. what gives?

When I taken the tire off, there was nothing sticiking in it, i ran my finger inside it and it was nice and clean, and the tube had a little hole in it which didn't look like a cut, but more like an imperfection in the material (like an air bubble?).. I am happy it didn't happend while I was riding, but why did it happend? Is there anything I could have done wrong? are there better tubes I could try?

Thanks,

A.