Be able to distinguish congestion market trading from other types of markets that are more conducive to the making of profits.

I find the understanding and identification of congested markets to be difficult for many traders to understand, including professional traders. So when the price action changes on them to resemble congestion prone to short moves and whipsaws related to the setups they do trade, they still continue to trade as though nothing had happened. Then you see them end up with a predictable series of losses from positions they were whipsawed out of wondering what happened to them. Some of the more frustrated types that need to be in the action then start to trade the price wiggles further putting themselves into trouble that can spiral down their account. Add to this scenario a psychologically addictive personality type, and then watch the person go to ruin in short order.