You might think of some by later in the year though? Like you, I can't really remember any books I've abandoned - I tend to stick with them until the bitter end however crap they are!
Books that I find intimidating tend to be excessively long, boring (in my mind that often means historical and/or most of the 'classics'), or ridiculously complex.
So, for me, intimidating includes War and Peace, Lord of the Flies, Frankenstein, The Bible (!), Gormenghast, anything by Thomas Hardy, Don Quixote, etc. I think I might give 'Cloud Atlas' a go as a book that intimidates me and that's only really because I've heard such conflicting views, and the format seems so odd, that I fear I might be wasting my time - plus it simply doesn't really 'appeal'.