I'm not one of those people who worries about the US or UK governments spying on me – I have nothing to hide and even less which anyone would find interesting to read. Superficially, granting the FBI access to data in order to protect innocent people from terrorists makes sense. However, if Apple allowed the British and American governments access, how could they refuse to do the same for the Chinese, Russian, Syrian and Sudanese governments? Moreover, it is quite easy for terrorists and crooks to apply their own, equally effective encryption – something they would certainly do if they thought Apple had given the FBI a 'back door' to their encrypted data.
And what would the FBI, CIA, NSA, MI6, MI5 or GCHQ do with data (which might well include bank details) gathered from you or me in the process of a misguided investigation? They'd store it on a government computer. They'd probably store all the details of how they can access all this data too. And then someone like Snowdon comes along and starts publishing it all.
I really want then to catch terrorists but this is not the way.