Another lifetime ago, I used to work for a large rental car company in Metro Detroit as the general manager's assistant. To say that an administrative assistant's job is simply clerical is a gross understatement and would likely cost you some serious suck-up points. Whatever the manager can't get to typically falls right into the lap of the administrative assistant. If you want to get anything done be very, very nice to the administrative assistant.
I was expected to do everything from creating training manuals to planning quarterly and yearly managerial parties to handling customer service inquiries, to finding competent and cost-effective vendors, to picking out carpet for our new corporate headquarters. I actually worked side-by-side with an interior designer for months to select carpet, workstation cubicle colors, art and window treatments for our brand spanking-new building and I knew less than nothing about interior design. I was expected to make the decisions because my boss had no time (or inclination) to but needed to sign off on the decisions anyway.
When I first started my job I was a little taken aback by the vast pool of knowledge I was supposed to have. People expected that since I was the GM's assistant I must know about "x" and surely had some insight into "y" and clearly could make x + y =z. My boss was on the road a lot so he would simply ask me to handle whatever came across his desk. The more I completed on my own the more my boss gave me to handle. Whenever I complained to him that I could not complete a task because so-and-so wasn't cooperating, returning my calls, sending an invoice, etc. he would simply say to me "I don't want to hear the excuses, just show me the results." He wasn't necessarily being mean or callous. He just didn't want to hear, nor had the time for, the particulars. The only thing that concerned my boss was that his to-do list was getting shorter. Sometimes I felt overwhelmed by the decisions I was entrusted to make, but the autonomy in my job was the trade-off. I was pretty much allowed to do what I wanted as long as the task was completed on time.
I have used the "no excuses, just results" mantra more times than I can count in both my personal and professional life since then. I was forced to own my decisions back then and I have willingly owned them since. It is infinitely easier to take responsibility for your own decisions than to place blame. To place blame you must include others and hope like heck you can really prove they have mistreated you. What a waste of time. Regardless of whether you are right or wrong in your perceived mistreatment, who really cares? Your boss doesn't care. The amount of time it takes to prove your case could have been better spent simply taking responsibility to fix the problem in the first place even if it's not your fault. We all know life isn't fair and in the working world it's even less so. But, it takes self-motivation to get ahead in both work and in life. Rely on yourself to get things done instead of complaining that other people are standing in your way. In the words of George Washington, "It is better to offer no excuse than a bad one."