What is the worst part, personally, about transitioning into civilian life?

Embrace the change! If you find an organization with leaders whom accept and respect your leadership than stick with it IF not then move on until you find YOUR heart desire to grow and improve the organization! YOU have much to offer!!!

I don't want to get into the negatives because I just don't think that will help you much. The biggest thing you have to worry about is your quality of life and I am positive you will do that.

The one thing you need to be doing, is networking. Go meet people, join local groups (of veterans, etc.) and let people get to know you. It's hard to transition from the military not having like minded people to lean on daily. Doing this one simple thing will be super beneficial for you and will make most of the worries you have seem unimportant.

Can't count the number of times I mumbled "can't wait to get out and not work with stupid people".....

Turns out, most of the stupid people are not in the Army

I'd say it really depends on how GungHo you are about the service. If you are expecting things to run like the military where there is respect and discipline, the transition is going to be tough. I got out under a medical discharge as well. I found it very difficult and, 18 years later, still have issues with things (just not nearly as significantly as when I first got out). There is no easy solution to helping you overcome those issues. Only thing I can recommend is to adapt and overcome.

The Cartoon you posted does speak the truth. Some of the problems I have dealt with are basic things, e.g., showing up early to be prepared to either take over or get the COA under way promptly. Dealing with P.C. nonsense and inadvertently hurting someone's senses when I was simply relating facts (in our way), concentrating on "Mission Success" and not the side bars and waste of time. There are many factors which will have you step back and do a WTF appraisal but before you let loose with a tirade, remember where you are at and act like a native. Making new friends will help and make transition much smoother. Take advice and critical help serious and grow.

For me it was learning to relax a bit. I was used to the structure of the Marine corps and found it difficult to work at a civilian pace, if you will. It also took me some time to umm accept and tolerate the suckups. I was a bit harsh at first but that gets better. One thing I never got over is having to deal with complete cluster Fs. To this day I cannot stand disorder, and I've been out 25 years. I guess some things are just going to stick with you. I eventually found that I worked better alone, in a position where I was responsible for my own actions and I didn't have to deal with the mess. If something happened on one end I just called and made adjusents on the other end, that is just me. Some of my buddies had no issues transitioning back to civilian life.

After my deployment, it was being part of a team.
Also learning not to use foul language sometimes.

The biggest problem I had was adjusting initially to the GI-Bill levels of income from a Captain on flight status because I needed to prepare for a civilian compatible career field. Apparently dropping bombs in the civilian sphere is frowned on. However, I was able to get into the reserves for a part time job and it worked out fine. I got my training and have been a computer nerd for over 30 years. Is this a great country or what?

You are entering a whole new world and no one will really care what you did before and you will have to prove yourself all over again. In many companies rules are vague but I have seen a few make the mistake of going on too many long lunches and such. If you think the military had the politics you haven't seen anything yet and many companies have no clear promotion guidelines if any at all. Many jobs can be rewarding though and find a fellow vet there who knows the ropes and learn from him/her. It is strange at first but you military experience will enable you to follow through.

Find a goal! Find and maintain friends who are what you spire to be. Never allow can't to enter your vocabulary. Never allow your experience to be discounted by you or anyone else. Never think you are above doing something, it's the things we don't want to do that teach us the most. There are a lot of sorry ass excuses for human beings out there: treat them with respect. There are a lot of good ones to. And #1 never, ever, ever freak out! You know what to do next, do it:) Never stop learning.