It's almost as if people are not capable of multiple emotions at the same time..... This makes me sad, angry, and a bit surprised.
Is that allowed?
Nope. Do them sequentially.

/s
It's not about how many emotions you can experience at the same time. It's about complex emotions being made up of base emotions and everything we are incentivized to do tying into how we feel (intrinsically or emotionally). There are a lot of possible variations. But that doesn't change the fact that all base emotions associated with disappointment are negative emotions.
The whole point of negative emotions is to incentivize us to fix, resolve or avoid something that negatively affect us. If you are repeatedly disappointed (whatever mix of sadness, anger or disgust it consists of) by the same thing, then your expectations are objectively wrong. Your disappointment is telling you to lower your expectations. It isn't telling you to fix the root cause of your disappointment, because you're not disappointed in yourself. You can't fix the root cause. You can only fix your expectations. Or you can keep getting disappointed and reinforcing that feeling (which will only make it grow stronger).
The connection between emotion and cognition isn't a one-way street. How you feel about something is influenced by what you think about it, and what you think about it is influenced by how you feel about it. That's how changing your perspective can resolve emotional turmoil. Experiencing prolonged negative emotions is detrimental to your mental state.
Ergo, you should make cognitive choices to focus your negative emotions on things things that matter, preferably things within your control or at the very least, something you are capable of influencing. If you live on the North Pole, there's no point in being pissed off at the snow.
Things like this CAN'T make me feel bad because they're both out of my control AND unimportant. The only thing I'm invested in regarding WVM is that I want to see where the story goes. However far that may be. Even if he doesn't finish it, it was an interesting story whilst it lasted. The only thing I feel towards it is curiosity (which isn't an emotion but an intrinsic motivation).
This is actually pretty fun to talk about. Thank you for your sarcastic joke. Really revitalized me.