Executive Summary
Fear of being wrong can result in never taking action without explicit permission. The issue is that often times the opportunity cost of the question to your boss is greater than the consequences of being wrong and/or using common sense will result in a perfectly fine solution that won't cause any problems.
Most companies don't want drones who are only able to get something done if told, and who can't act on their own without direction. If a manager spends all his time telling others what to do with specific instructions, it won't increase efficiency as much as teaching others how to do things without specific instructions.
Instead of asking your manager about these things, you can either:
- Just take an educated guess about what should be done and do it
- Inform your manager about what you plan to do and see if he has objections
Micromanagement is Inefficient
From a previous answer:
Give a man a fish...
If you ask me what the current rate between JPY and USD is, I can tell
you (about 95 JPY/USD). If you need to know the same thing again next
week, or next month, and I'm not around, what will you do?
It may be efficient in the short-term to just tell you to use 95, but
long-term if an important part of your work is knowing what the JPY to
USD rate is, it's much better for me to teach you how to figure it out
rather than just telling you the answer.
Now many people may assume this means I should just give you a
link and then it will
all be okay because you can find it next time. Problem solved, right?
What happens if you need to know the rate between USD and EUR? What
will you do then? Of course I can give you another link, but then you
will just have two separate links, and run in to the exact same
problem if another currency is required.
This is no good.
Teach a man to fish...
What many good bosses will do is to ask you to think about it. When
you think about it, you are developing problem-solving skills that can
be used not just to finish the current task, but to be able to tackle
future issues you aren't perfectly trained for.
So maybe it would be quicker to set up this computer if your boss told
you the server name. But what happens for the next computer? Will he
need to accompany you every time you set up a computer so that you can
know the server name by asking him?
"It's easier to ask forgiveness than to ask permission"
For something of low consequence like a cable, you could just do what you think is right and put it somewhere appropriate. If it ends up being a mistake, you can apologize, and ask what your boss would prefer. This will give you more insight in to what he/she wants next time.
Rather than upset your manager by asking questions about every task you get assigned, it is easier to upset your manager now and then when you make a small mistake, and just apologize for it.
Disclaimer: If the task is something non-trivial that could have serious financial or legal consequences for the company, this approach is not advised at all. Things like company policies for cable and key storage, however, is probably not a task of critical importance.
Explain, don't ask
If you feel uncomfortable taking the leap and just making a decision, you can at least soften the way you speak to your boss.
If your boss asks you to store a cable and key, rather than asking, you should tell.
Asking
"I thought that company policy was not to store keys out on the desk, where should I put it?"
Explaining
"I am going to store the cable on the shelf, and the key in the cabinet over there, ok?"
The first approach requires your boss to make a conscious decision for where to put it. This requires a lot more brainpower than the latter, which he can just say "ok" to unless he has a serious issue with it. The latter shows more respect for your boss' time and brainpower, which is generally a good thing in the office.
Experience Comes from Mistakes
If you are too afraid to put away a key because it may be the "wrong" choice, you are hurting your education and growth. Remember the first time you did something really wrong when you were a kid? Maybe you swore in front of your parents, or didn't come straight home after school without telling your parents where you were going? Those are experiences that stick with us because we learn from mistakes much more easily than from doing things right.
When you're young you have the benefit of being given tasks which usually don't have massive consequences if you screw up. That means it's a great time to make decisions on your own and learn from the times you make the wrong choice. It will help you form a good idea of how to judge a good idea from a bad one, and make you good at apologizing (which is a skill that will serve you well for the rest of your life).
No company expects an employee to be flawless. They expect employees to be honest and motivated, proactive and constantly improving, but nobody expects perfection.