Not being able to explain what i've read out loud.
One thing that I can't ever forget is when I got called on to read a passage out loud to the class followed by a question from the teacher asking me to summarize what I just read.
Somehow I thought I could hide my embarrassment by not responding which in turn just created an awkward silence. I didn't want to admit to the class that I had no idea what the hell I just read. This happened to me more than once, and I swear they can tell by the way I read because they never asked anyone else to summarize or explain. After those incidents they learned not to ever call on me again for the rest of the class year.
I can listen and read to myself, but this particular thing never went well with me. I'd like to believe it was because I was timid and didn't like being put on the spot, or blank out when reading something uninteresting, but I'm probably just an idiot.