Micromanagement plays out as a constant barrage of needing to be updated on every single detail that you work on. It's immensely tiring, and essentially comes from the manager not really trusting you and exercising too much control. They need to know about every action you take and how long is it taking (and why is it taking X long). It's horrible and drives people to look elsewhere. Project managers also fail badly at this. They badly manage the customer and try always be a 'yes' man to every whim they have, and end up driving the engineers crazy by wanting constant updates hour by hour.
With my new manager, by him checking in with me more frequently to see how things are going I can gauge my performance better from his reaction, pick up on errors I've done early on in the process that I wouldn't have spotted myself, and build a better dialogue with him. Frankly, if this comes from the manager not trusting me then I don't blame him; he shouldn't - I'm an idiotic 20-something year old. I haven't built that framework of expertise where I can do a job without error or guidance.
Conversely, a 'hands-off' boss for me meant that I'd be working all day, only to hand in the work and find out I'd done something completely wrong and needed to re-do things from scratch. I might be doing a job as I've read in the spec, but it turns out there's some common practice way of completing it that I'm just expected to know right off the bat. I wouldn't know what the intended outcome of a project was, because I had never completed a project before.
Micro-management is like captaining a boat. If the skipper constantly corrects the course, he'll exhaust the crew - but if he doesn't correct enough, the boat can veer off rapidly with no one at the helm.
I'm sure for Google, who generally hire incredibly talented engineers right off the bat, a 'no-micromanagement' policy works well; but for a fresh-faced undergraduate straight out of a second-rate university, micro-management and mentorship is crucial. Something that might take a junior hours to do can be solved in minutes with a bit of guidance. I think sometimes the senior engineers I work with underestimate how much knowledge they have to share, and overestimate how much knowledge a 20-something year old engineer with one internship under their belt has.