The combination of Hello and Picasa was a productivity drug.

You had your deck of cards, a computer full of perfectly organized images, the opponent had his own deck. You would show some art work or photos, they would give their opinion about it, each round you would show x more works that you thought more suitable for their taste. The other player would take their turn whenever they felt like it. What they showed allowed further fine tuning the following selection until eventually you arrived at wanting to show works you didn't get to make. You debated the plan of action and the opponent waited impatiently for days, weeks or months for the follow up session.

It's weird that people still call it Google Picasa and Google Hello as google contributed nothing besides freezing it and shutting it down.

Seconded. I haven't still haven't done anything that does face identification and grouping as well.

Picasa was incredible. It would provide instant search based on the filename, folder name and metadata on all images.

Images purchased as stock have a lot of metadata in them.

So Picasa was able to act as a cheap folder and metadata based digital asset management system.

It still works though.