Google Maps - resource hungry, always doing something in the background, slow .. replaced them with much better, unfortunately local, alternative
Google Play - two examples: doesn't prevent phone from losing network so I have to play with the phone in order to download updates; listing my applications always takes about half a minute.. even if I did the same task 5 seconds ago
Google+ - basically unusable, unbearably slow, doing stuff in background all the time, crashed whole system few times
The truth is I don't have the most modern phone, but it isn't the slowest either (it's single core 900MHz w/ 512MB ram). It's running on the latest available android for that device (the device was sold less then a year ago, it's from 2010). Can't imagine how those apps run on older/slower phones.
Side note: Another multi-billion dollar company that can't seem to produce working android application is facebook. That is the single worst application that I have ever used (some were worse (google+), but I can't really talk about "usage" with them). It's getting slowly better, but it's still a crap. Twitter on the other hand is great.