I have actually learned some handy tips about how to better manage my account and "friends", thanks!
I can relate to so many previous posters. My pet peeve is MIL, she actually accesses FB from both hers AND FIL's account, so you never know who is commenting. Actually that's not true, she's an absolute nitwit so it's pretty obvious most of the time. She's a classic "thread-killer": I'm a sporadic status-updater at the best of times, and I go for quality over quantity. I like to think my posts are fairly well thought out and humorous or a bit interesting, hence they tend to get a lot of comments/likes, but often MIL will bumble into the discussion and make an extremely random/misspelt/inappropriate remark and BAM! - discussion over!
Here's a recent example, commenting on a thread where I had posted about a travel experience (loads of other friends had already shared their travel stories beneath my original post, ranging from funny airline anecdotes to someone who had been thrown in jail for a night): "couldn't get me ther for all the tea in chinga no way once when so-and-so (random friend of hers who is not on facebook) and I were in Hobart we saw a sick dog in someone's yard it was so sad"