I got caught out by a bug in android recently that I want to share. This bug is very specific to people in the UK and won't affect everybody, as I will describe below.
Google mail came out yonks ago, and when it did, everyone in the world happily went about using firstname.lastname@example.org - except in england. Due to various legal wranglings, google was not allowed to use gmail.com over here, and so instead used email@example.com
(As it happens, early adopters did have a gmail.com address, which got silently translated into a googlemail account instead.)
Recently, google managed to get the rights to use gmail.com in england, and so everybody in the UK has the option to switch to the new, easier to type name that everyone else in the world has been enjoying for ages.
Now the android bug bit.
If you have an android phone and set it up before you switched from firstname.lastname@example.org to email@example.com. them your android phone is still pointing to the old address. For the most part, this doesn't matter - google silently translated between the two addresses. But there is at least one area where this does not happen - google sync.
Or rather it does, but only when updating the contacts on the phone. When you try and push updates to google (for example, adding a new contact on the phone itself), the push to google silently fails. It then helpfully, resyncs your phone, and the contact vanishes.
The solution is unfortunately a pain in the arse. You have to change your Gmail account settings on your android phone to match your new firstname.lastname@example.org account.
But, the only way to do this is to perform a factory reset.
This isn't quite as bad as it seems - you will lose the contents of your internal memory, but your SD card will not be touched. As long as you are in the habit of adding your contacts to online accounts (google, outlook, etc) they will resync once you set the accounts back up. Also, any applications that you downloaded will still be available to you in the market place, and can easily be found under the downloads tab. This includes purchased apps, so you don't have to buy any of them again, and don't have to hunt around for them.
Even so, this is a pain in the arse. You will lose your screen layouts and need to recreate them, you will need to type in all of your account details again, and you will have to go through the oh so helpful tutorial screens that you really don't need to after owning the phone for 6 months.