This would probably get better answers on http://english.stackexchange.com/https://english.stackexchange.com/
I expect you to talk to me regarding [...]
You're stating very clearly that they have to talk to you regarding [...] If you have the authority to do so, this is perfectly fine. You do not need to be the manager of someone in order to make statements like these. There are countless situations where you're allowed to expect others to do something. People don't say "could you pretty please attend my meeting?" if the meeting is mandatory.
Of course if you're asking them for a favor and phrase it "I expect", that's wrong. There is a difference between asking for a favor and stating an expectation. Using the same language for both creates trouble
... and not wait for things to happen
This is a veiled accusation that you assume they would "wait for things to happen" if left to their own. This can be interpreted as a reprimand.
Please do so in the future.
This strongly implies they did not "do so" in the past. I.e. they did not satisfy expectations, and they did wait for things to happen. In this context, this is a reprimand.
Conclusion: Unlike some others, I don't think "expect" is the core of the issue here. If you need someone to do something, don't say "I was hoping you will" or "It'd be better if you would", that only introduces harmful ambiguity - use these terms when you'd like them to do something but can't expect them to do it. In a professional environment, you can tell your coworkers if you expect them to do something, and they can answer that they will or won't do it. But if you reprimand your coworkers, as you did, you need to expect that some will take it badly. Especially so if you CC the reprimand to 10 people.