Absent Characters and My Inflexibility Lead to a Not So Great Session I'm Afraid

First off I need to apologize to everyone that actually made the game. I was feeling a little down since some of the planning that I had done for the week's adventure was rendered null by the fact that none of the characters that I had specifically planned things for were able to come to the game. I feel that my attitude rubbed off a little on the game and the mood was just not as great as in previous sessions.

The game this weekend was supposed to be great. Because I want everyone to explore their characters a little more, I deviated from the plot point campaign and developed my own encounter to help bolster the role play; I had planned specific things based on the backgrounds of some of the characters and hoped that that would trigger a chain reaction wherein other players could get into the spirit of really roll playing their characters.

I'm not going to get into specifics, because I think I'm going to try and resurrect some of the ideas next session. We ended up starting late, much later that normal late—also my fault, so I really couldn't run the session as deadly as I had planned, there simply wasn't time.

I started things off with an Interlude session that generated bowling for trees, and almost broke the plan for the evening—due to the interlude providing needed items that the planned encounter was supposed to provide. I had to resort to GM fiat, I hate that.

We only ended up using half of the giant map that I made for the encounter (and I forgot to take pictures because I was thrown off by the unexpected variables).

In planning the session, I had even tried to come up with specifics for every character's background, because I know that things never turn out as planned. In fact, I can say that I've learned the only constant in running a Role Playing Session is that nothing works out how you plan it. I didn't manage to figure out things for all eight characters. (Please don't feel left out if I didn't plan something for your character; and know that I tried and that it was on my mind.) I had worked up three really good ones and all three players were unable to come.

This is definitely a failure on my part as GM, unable to be as flexible as needed, and unable to improvise alternates on the spot.

It just wasn't a good week for me. Hopefully I can get back into the groove for next session.

Update: P took a picture and linked to it in his comments. I'm adding it to the post for all to see.
(As always, click for higher rez)