Sometimes co-workers and even family members say things to one another that they wouldn't dream of saying to clients or even perfect strangers. (I always liked the term perfect strangers. They're only perfect because we don't know them.) We simply don't always give our co-workers the same level of consideration we provide to our clients. And it's our clients who pay for it.
Making one another feel appreciated is not management's job alone. We all have to play a part. Be kind. Express appreciation. Go out of your way to help a colleague. Create a positive work environment. Think about how great your client service could be if everyone worked together in this fashion each and every day.
The person sitting next to you comes first; the client comes second. Employees are happier; the workplace is more productive, and your clients get better service. How 'bout giving yourselves a hand!