Interruptions happen all the time. They can be annoying and irritating. The last thing you probably want to do is to keep track of them in a journal.  

That's exactly why you should.

Keeping track of interruptions (by day and time, with details of who and where) will reveal to you a pattern. The pattern may consist of the same person (people), or the same subject matter, or the same time of the day. 

Once you identify the thread you can take steps to handle the pattern. It will take as much time and effort to address the pattern as it does to address the interruption…but you'll only have to do it once.