Do not be mislead by the title of this page: Android by and large is the best mobile operating system out there however as a fan of it, I cannot help but notice certain things which warrant attention and should be fixed right away because they are simply crucial.

Problems (applicable to Android 6.0 Marshmallow/5.1 Lollipop)

• Android features the best UI paradigm of all mobile OSes out there however the sad fact remains: Android fell victim to the design philophy introduced by Microsoft in Windows Phone and later Apple in iOS 7.0. Android UI is an incomprehensible mess of various completely different UI implementations which drive the user mad.
  1. There is no clear distinction between text and control elements.
  2. In Google's own applications various similar UI elements can be controls or text at the same time, i.e. in application a something is clickable, in application b it's not.
  3. Various Google's apps use very different design UI paradigms and implementations. In short UI in Android is a total incomprehensible mess.
• Upgrade hell: Google has yet to solve the problem of upgrading various devices based on Android. The only devices which receive regular updates are Google's own Nexus devices. As a result almost nine out of ten Android devices are exposed to at least one of 11 known critical vulnerabilities (PDF).
• There's no way to exclude certain apps from automatic updates. It's a common situation in Android when newer versions of apps are worse then their progenitors (require more undeeded permissions/include ads/drastically change UI for the worse/remove crucial features/etc.).
• There's no built-in option to roll back apps updates.
• Bloated ROMs/bloatware (if possible buy devices using vanilla Android, like Nexus devices or devices based on CyanogenMod).
• In most cases you cannot uninstall built-in apps. In certain cases you cannot even disable them.
• Google Drive backup doesn't allow you (by default, without using third party apps) to backup folders under /sdcard or any other path.
• Backup hell: Android even at version 6.0 doesn't allow to create full backups of your device:
  1. Android has a feature which prevents the backup of certain applications.
  2. Android has no means of backing up calls history and SMS/MMS databases (at most you can export them).
  3. Even without the two issues listed above, there's no official solution of backing up your entire phone to your PC.
  4. Most applications in Google Play do not store your settings in the cloud which means there's no easy way to migrate your settings to a new device.
• Filesystem mess:
  1. Android doesn't keep track of the files created by various applications in /sdcard so upon uninstallation of the said apps various cruft may remain.
  2. There's no easy way to reconfigure apps to use an external SD card for storing data.
  3. Internally Android is a mess of symbolic links and FUSE mount points.
• Some apps include very annoying full screen/video ads which consume tons of traffic.
• Market lock-in: once set up Google Play will always show in the language of the country of your origin (to be precise it depends on the country of your cellular operator or credit card). Also, for instance if you're a user from France Google Play will not allow you to use apps which are meant for the US market. Another bummer is that you will have to watch Google Play movies based on this language alone without the possibility of purchasing movies in any other language.
• Android OS by itself has a very high memory use: Android 5.1/6.0 is barely usable on devices with 1GB of RAM. All vanilla Android 5.x releases have a major memory leak bug.
• Google loves to ignore critical bugs in Android.
• Android does not allow you to set mtime (modification time) for files under /sdcard unless you are root.
• Android does not allow you set CPU/GPU frequency policy unless you are root. In many cases this is a nice nifty feature to limit your maximum performance to preserve your battery. Thousands of games and apps in Android are sloppery coded and consume 100% of CPU even though they do nothing useful.
• Android processes management is totally fucked up - you never know what is really running, how much RAM it is really consuming and you cannot really stop/kill offending processes/tasks/applications.
• Developer: Android NDK doesn't support files larger than 2GB.

Why Android is the best mobile OS

• Android is extremely customizable: pretty much every component of the OS can be swapped.
• A plethora of all kinds of devices for every wallet.
• Deep Google integration.
• A fine selection of apps in Google Play, along with news magazines, books, music and video.

In conclusion

This is work in progress.

Leave your comments, additions and hatred below.