Guess the source of stress

UPDATE: I AM going to tell you what this is soon, but no one has guessed it quite right. Any second guesses? Hint: it caused me many problems for almost a whole year!

a) What is this little do-hickey, and b) why did it cause me so many problems?

If you guess correctly, I will ooh and ahh about you all day as well as create a link to your blog in my next post. Don't have a blog? No worries. I will ooh and ahh about you on my next post instead.

So get guessing! :)