Lol, love it.
Well, I'm scared to say this, because I said it when I first got my Bionic, I love my Galaxy S3. Some of the stock apps like the email, screen locker, messenging are great, in my opinion. I dropped a few of the apps I used on my Bionic, didn't need them on my SG3.
Hopefully I haven't spoken to soon. But, this phone is fabulous!
I don't know if this is what is causing your problem, but I had the same message and it was because I checked the box "Do Not Keep Activities" which is in the settings, under developer options, under apps.''Unfortunately Messaging App has stopped working"