There will be some who will feel the urge to correct that title: surely, it should be " ... something of which to be afraid"? Well, no.
It was only yesterday that I heard the latest book on correct grammar being plugged on the radio (My Grammar and I by Caroline Taggart). Now I have no objection to books like these (I'm working on a practical grammar e-book ...), but there is a problem.
The message that we are fed regularly is that there are two types of grammar (right and wrong) and two types of people (grammar pedants and stupid). It's no wonder that people are wary of writing.
The most important thing about writing is meaning. Grammar and punctuation are there to make meaning clear. If you concentrate on that, you won't go too far wrong. So yes, people were once taught not to leave prepositions (like "of") at the end of sentences. But did you struggle to understand what I was saying? I didn't think so.
Don't be put off by a fear of getting it wrong. Just make yourself understood.