For what it's worth I highly disagree with a lot of the opinions in here.

Waiting prioritizes clear communication at the expense of some time that is almost always justified. People who wait are typically detail oriented and have the infamously prevailing cooler heads. They're the ones actually getting stuff done while management impatiently glances at their pathetically underspecified checklists.

Interrupting prioritizes a false sense of efficiency and just seems like weak impulse control or a bad short-term memory. Every interrupter I've ever met is disorganized and unreliable.