Is there something in particular people do that just attacks your last nerve?

I got blown off today. Again.
It isn't enough that I have 1 person outside of my boyfriend that I hang out with, but I continually try to make plans with people so I can establish more reasons to do something. So, I baked with this girl last semester and she called me this weekend freaking out about some girl and blahblah. Then, all fo the sudden, she missed me and made dinner plans with me for today. I woke up feeling great, took a nice shower, did my hair and makeup, had an actual breakfast, and went to class early. I was very attentive in class, answered all the questions, helped some people in lab, and had Quiznos for lunch even though I wanted Chick-Fil-A (hey, that was a huge deal for me). Anyway, I get out of class, wait for hers to end and text her asking if she needs time ot get ready (she doesn't drive) and what do I get? "How's 7 instead?" Well.... our plan was for 4 and I'm really hungry so... I go to sleep. I wake up at 6:30 and she says she's busy, sorry.
I am so livid! My hair looks really nice and I wanted to go out and maybe feel pretty. Feel like I have some form of a life :/

Sorry for the rant, but being blown off ticks me SO BAD! Now I just want to stay in and be pissy about it, but my boyfriend wants to come over. Not in the mood for company >.<