What about an emotionally based response as a barrier to stepping up / intervening in a situation? For instance, fear, anger, anxiety…

The section on Strategies for Effective Helping has many different tips and ideas for overall effective intervention; certainly this is a valid question. If direct intervention is not an option or not preferred, remember that indirect intervention can also be very effective. Intervention can also come after the fact and be effective. It really depends on the situation. Also remember our S.E.E. model (Safe; Early; Effective). Safety must come first!