Thankfully, I'm far enough along in the process that I enjoy the break too whenever my therapist takes one ... Of course, early on in the process I'd be all kinds of messed up if I missed one session for any reason!
I've come to realize that therapists are human beings just like me and that human things impact there lives just like me, therefore, I don't get overly upset when they need time for themselves to tend to their human needs ... Nor do I feel it necessary for them to explain to me why that is ... For all I know they could be taking a new course or attending a seminar to learn new information that could even prove helpful to me and my recovery process.