Does it make you angry when people cancel at the last minute?  

Yeah this would make me angry. The next time they asked me to do something I would cancel out on them.

Sorry to hear that. Yes that would make me really angry because I don't think they know how to respect other people's time and schedule. Everyone's time is important, if the schedule is already fixed and a diary is already marked, I don't see the point of moving it or canceling it at the last minute, unless emergencies come up and those would be totally understandable. If they ask me out next time, I wouldn't even promise to go out with them because I won't trust them anymore. And of course, I wouldn't even invite them to do anything with me.

I don't know about angry..maybe hurt. Ask them if Saturday would be better. Or ask them if they would like to be excluded until a better time for them. Talk to them. If they are friends, they would have to try to understand your point of veiw.

I think you should consider the fact that their absence on your Friday night activities might mean that they are not interested playing Dungeons & Dragons. Maybe you should ask them what it is that they really want to do, not exactly what you want them to do.

It would make me angry as well. I would probably confront them and say, "It bothers me to never know if you're going to be there or not. If you don't want to anymore, just tell me. I won't be offended." I really hate when people cancel last minute, unless it is for a very good reason! If it's not for a good reason then it is just inconsiderate and very annoying, because you could've made other plans instead.

I think to cancel at the last minute is definitely not a nice thing to do. For one, I could've made other plans or I could've spent my time doing something more productive rather than wait for others.

Yes ofcourse, i will get angry.
It is really annoying when people canceled your appointment even you've been ready for it and you're actually waiting for them to come.
I will tell them straight as i am a straight forward person that they have to be responsible and don't waste other people's time as its very valuable.
Cheers and have a nice day ahead from Francis.

Of course I get upset because I've put much time and effort into preparing for that event. Standing me up is definitely going to cause one big fight, if I were in a relationship. I hope that the persons would inform me beforehand that they wouldn't make it, so I wouldn't have to wait.