I find it fascinating that the environment in which people work can have such an effect on how those people present themselves, both in terms of their style of communication and (more surprisingly) their physical appearance.
For example, I have a friend who used to work in a department which had little team spirit, where the leadership was poor, and where people were by and large not very friendly or helpful. Her reaction to this situation was to dress severely, to scrape her hair back in a tight ponytail, and to adopt an abrasive attitude. All of this actually reflected the fact that she felt unhappy and insecure in her work environment.
My friend then moved to a new department where the atmosphere was quite different. People were friendly and happy, the team was tight-knit and the leadership was good -- and she changed accordingly. She started to wear her hair down, she was smiling and more relaxed, and she adopted a much more approachable persona. She was working in a better place and her behaviour and appearance reflected that.
Employers often seem oblivious to the effect that the company atmosphere has on employees and their behaviour, but this effect is profound. Cultivating a good company spirit results in happier and, I'll wager, more productive employees.