Between here and there, or "What is this session lacking?"

Picture this: through trials and tribulations, you have managed to get a session on the road. Your friends are gathered, your snacks are in place, and everyone is ready to have some fun, or at the very least kill some time.

You start playing, but it progressively becomes clear that this is not working out for you. Something's missing. You're sad.

What could the missing ingredient be?

Here's an informal list:

1. Something in your personal is bothering you, biting and scratching under the surface of your consciousness. Ever there to gnaw and annoy you.
2. You try to forgive and forget, but someone present wronged you in the past, or at any rate you had a minor kerfuffle. The bond of trust is broken.
3. You're alright, but at least two other players are clearly not getting along. For whatever reason.
4. You think the damn GM is lying about their rolls.
5. You feel taken for granted, and not in the company of friends.
6. Everything's alright, but lukewarm at best. The story is just not that interesting to you.