When does a message queue add unnecessary complexity?

I've been noticing message queues everywhere lately, even for stuff that seems pretty simple, like just getting two services to talk to each other. On one hand, they're awesome for decoupling and managing traffic spikes. But on the other hand, having to manage yet another piece of infrastructure, worrying about message delivery guarantees, and dealing with potential eventual consistency issues feels like overkill when you really just need to send a quick notification from service A to service B. What do you all think? When do you decide, 'Nope, this simple async task is fine without a queue'?