whereas 为从属连词，表示对比意义。从句位于主句之后时，分析为对比状语从句（=while on the contrary)（夸克的分类）；从句位于主句之前时，分析为让步状语从句（=although）。词典例句：

Doctors’ salaries have risen substantially, whereas nurses’ pay has actually fallen.

Whereas knowledge can be acquired from books, skills must be learned through practice.

你看到的那个句子是口语体，不是很规范。whereas不该另起一句，而应该作为前一句话的对比状语从句。另外，该句中as从句后漏掉了动词be。

Perhaps my expectations of lunches, water-cooler gossip and caring, deep-and-meaningful conversations were a legacy of the last time I was in that kind of office environment，whereas now, as I am near the end of my fourth decade, I realize work can be fully functional and entirely fulfilling without needing to be best mates with the people sitting next to you.