-- Android resets your phone to factory settings without asking you or even giving a warning if you port a number to it. This deserves a class-action lawsuit. See here: http://androidforums.com/droid-x-support-troubleshooting/131...
-- Using the built in email application, sent emails often stuck in the outbox. See here: http://www.google.com/support/forum/p/android/thread?tid=6d4...
-- Wifi on the phone does not work if SSID is hidden. See here: http://code.google.com/p/android/issues/detail?id=1041
-- Bluetooth on the device is unable to connect to a desktop to transfer files or sync. See here: http://www.bing.com/search?q=android+bluetooth+paired+but+no...
-- Once you sign in into Google Account using any Google app (like Gmail), you cannot sign out, ever! Only way to "sign out" is to reset the phone to factory defaults, which means loosing all your data and needing phone activation again. See here: http://www.sizzledcore.com/2009/12/27/how-to-remove-change-g...
-- They have artificially blocked use of Google Calendar app on the phone from functioning unless using a Google Account. Of course Google isn't interested in Outlook Sync, but even third-party developers suffer. Many have started providing their own calendar apps. See here: http://www.syncdroid.net/
If you follow the links, you may notice that many of the issues have been open for a few years, some since Android version 1.6, etc. Google just does not care.
To fix the issue with sent emails stuck in the outbox, people have started from the source code of the built-in email app and created K-9 mail, which is 10X more powerful, and works.