Am I the only one?

Frustration set in tonight on my way to our first sorority meeting of the new year (our "year" runs from September to September). There is a woman in our group that constantly has a reason she can't come to the meetings. And it's never a planned reason - like something that has been in the works for a long time and can't be changed. It's always a last-minute thing that pops up and it "turns out" she can't make it. It's just so frustrating for me. I was raised that if you make a committment to something, you honor it - even if something better comes up that you'd rather do. That's just life. We have to make choices about what we do. If you're not planning to fulfill your obligations, why make them in the first place? Of course this is also the person that is gung ho when new projects/socials/events are suggested and planned but then doesn't show up when it's time to put them on. Why should I be surprised? Ugh.