[georgemcbay]

"Develop a great little application/product that pulls you in and develops a decent user base only to have it disappear"

The worst part is when they do this with acquisitions (which Picasa was, though admittedly it was acquired quite a long time ago).

Also, even when they don't outright kill apps/services, it is painful when they basically let them wither on the vine (see: Google Voice, another acquisition of a promising product that Google snapped up and then basically put into hibernation soon after).