I have just started working in this industry, and so annoyed by the fact that managers are insensitive to the efforts put in by the developers.
1. They ask for estimates, and sometimes consider it to be the hard line for everything and then they make you feel guilty if you are not able to live up to them.

-- I am not asking to be always lenient but they need to understand that this is problem solving and one might not be able to gage the problem at first sight. A problem might have several sub problems or a solution to one issue might raise compatibility issues with other which were tough to foresee .

2. Why do they always want an instant response to their email or query, a developer being online isn't just there to answer your damn obvious and sometimes stupid questions which can be understood just be glancing at the logs once.

-- How annoying would it be if the manager himself is being poked every other minute for trivial things. Does he have the same patience with his/her developers?

3. In tough times the manager easily delegates the responsibility to the developer and instead of standing by his/her side, interrogates them as if we have done some crime.

-- Wasn't this approved by you. Weren't you the one who had these stupid demands before and didn't let me do things the correct or optimized way. I am not saying I am always right, but you can be atleast open for feedback or discussion.

Why are you the first to take credit for the success and yet hold us responsible for any mishaps.

It's sad to see that some of these people have been tech developers.
I can go on ranting for many more things.
I am not saying all those people out there are like this. But trust me many are.

Note: I am not seasoned as you guys out there. I may even be biased by my own experiences. But this is in complete contrast to what I was expecting when I graduated from college and was excited to finally learn by working.