The culture I experienced in the DC office was so toxic that I did not recognize the BCG I knew.
Some examples:
1) On my second project, a junior team member made fun of a colleague with mental health issues. When I spoke up against her remarks, emphasizing that a surprising number of colleagues - including "successful consultants" - suffer from mental health issues, the rest of the team (all from the DC office and including more senior members) reacted negatively. They in fact tacitly supported the junior team member and her remarks - which became evident when the same junior member received a MBA Sponsorship a couple weeks after this incident.
2) The career development advisors I've met (which are of utmost importance to your BCG career) showed truly toxic behavior. During performance reviews, I've heard things like "Your opinion does not matter" or "we trust our local associates more than people like you". This behavior from CDAs (a relationship that builds on exchanging opinions and impressions openly) would have been absolutely unacceptable in any other BCG office I've seen.
3) Programs to enhance people's work-life-balance get advertised over and over, but management does its utmost to prevent people from actually using these. A close friend of mine tried to use "Time 4 you" (a program where employees are supposed to get unpaid vacation very easily) as her mother was terminally ill. Even though there were no clear business reasons (say, an ongoing project she was on and couldn't be replaced), the firm built up considerable pressure (e.g.her CDA calling, asking to "consider her career") to prevent her taking this time off. Given the context at hand, this behavior was a text-book case of bullying.
4) Compared to other offices, I did not find a single senior role model in the DC office - quite the contrary. One example is how our team got "burned" on a low-prospect proposal, with the partner letting us work until after midnight. On Valentine's Day, we - against previous agreements to the contrary - had to crank out slides without real urgency until 9pm, before the partner let us leave, saying "I understand that some people have a private life and this day is important to them". It became clear to me that Mid-level colleagues (Project Leaders and Principals) get groomed to fit into this culture - turning "nice people" to cynical "slave drivers" in a matter of a few years.