A synagogue must have a window. Why? So you will not be so consumed with spiritual engagement with the words of tefillah that you forget that there is a physical world outside.
At the end of shaharit (morning service) today, I suggested the following: we've just spent 40 minutes praising God. Judaism also emphasizes the concept of hakarat hatov, literally, recognition of that which is good; find a moment today to tell the people around you how much you love and appreciate them.