Professionalism, at least for me, goes a long way in a work environment. Not to say you can't have some fun (within reason) and relax a little, but not at the expense of appropriate decorum. There is a time and place for different behaviors and unfortunately my past experience with people has not been favorable. When you're not at work; go crazy. You do you - within legal constraints.

Professionalism does not mean unfeeling, monotone, robotic, assembly-line behavior. Just be courteous, friendly, accommodating if possible. Put yourself in somebody else's shoes. Let your behaviors make a lasting good impression. Strive to better yourself and those around you. Be optimistic as much as possible. Nobody appreciates the alternative.

More and more I've come to appreciate the company that has made mistakes, corrected course, been through growing pains and learned valuable lessons. Young, small start-up type companies may be nimble, exciting and appeal to some, but that period of my life is behind me. The very large companies will probably not be personally rewarding and likely your tenure will be short.

Nothing is guaranteed though and things do change. The best you can do is to know your job; do your job; be compensated appropriately and go home happy.