Not only is Drive's search poor, but Google's own search results have been getting notably worse. Somewhat recently, they rolled out a change where some keywords in your query will be left out to generate results for something unrelated. I've been having to wrap everything in quotes, add plus signs, and/or click on the "no, what I submitted really was what I wanted to search for, thanks" links on the results pages. I really hate to say it, but half of my searches are done on Bing now where I don't notice this kind of behavior taking place.

Also, if you want to talk about bad UX on Google products, I could write a book on frustrations I have with using Maps.