Lack of built-in flash on OM-D annoying or frustrating?

Eric C wrote:

Well, in the case of non-professional casual use like an indoor group picture in a dark room or any pics at night, you will have no choice BUT to use flash. Therefore the lack of built-in is incredibly annoying. That's like having a point and shoot camera without a flash. (I don't know of any)

I understand purists who feel adamantly about using ambient light, existing light, etc, or if they're having to resort to flash using a professional giant one, but not including one really puts a damper on using it indoors at all....that's why I was curious how current users deal with this limitation.