The most annoying thing to me is that I don't have time to just sit down and write one. I'm a mechanical engineering major, so I barely have time to do anything but eat, sleep, shower, and study. I have to just set aside a few minutes to write a section of a review every once in a while.

Not being able to get privacy. If I'm writing a review and someone comes in and talks to me, it ruins my train of thought. Not to mention that I usually have to stop and hide the toy when someone enters the room.

Noise distractions. I always put my headphones on when I write but sometimes there will be kids yelling outside or a neighbor blasting loud music.

A few things, mostly when people keep walking around in the kitchen when I'm trying to get pics. Well that and when I reread the whole thing and decide it just isn't good enough but I can't think of what else to add to it.
@_@

I try to do them when my kids are quiet. If not I can't concentrate.