A few things to keep in mind:
1. Events get triggered randomly only once per playthrough
2. When you trigger an event manually, event conditions are ignored. Actor conditions still get checked though, but not if you used "Trigger Event (Same Actor)"
3. "goodcoffee == false" is only true if goodcoffee was explicitly set to false. But "goodcoffee != true" is also true when this variable doesn't exist.
4. Don't forget you can also add variables to idols. For example, you can add variable "coffee" to an idol when the first event get triggered. Then in some other event you may or may not add "goodcoffee" to the same idol. And in actor requirements of a third event you set that an actor should have "coffee" but not "!goodcoffee".
5. I think custom conditions don't actually work for events right now, only for dialogues. There is a custom condition "has_breakroom". You can test it: add a CHECK node with "Meta" -> "Custom" -> "has_breakroom"
I'm working on a small mod related update, so maybe I'll do something about it.
6. Also, if you add custom condition "high_prio" to a random dialogue, the game will prioritize this dialogue over all other events and dialogues. (meaning, when it's time to drop something on the player, the game first checks if any of the high_prio dialogues are triggerable).
Again, this only works for dialogues now, but I'll add it to events too