Phone calls, text message and email is what it did well. And it did exceedingly well.
The thumbwheel was just the right spot to quickly scan an email.
The keyboard is as good as they get.
The operating system was built to do exactly this and not that much more.
It is really hard to convey how great it was, without being able to offer up demos. I have bought keyboard add ons for iPhone and Android as they have become available and usually died quickly.
I even tried to get a company going to create a "blackberry look alike" on Android but in the end I didnt get financing and making Android be classic BB is not easy.
It was not good for games, web browsing, apps in general, but that didn't matter because it did what I needed it to do
BB from then on was a sinking ship, b/c they figured they would add all the features from the iPhone and Android to it. And eventually released an Android phone.
They lost focus on what the existing customers really loved.