6. Steve Rogers Jumps On A Grenade (Captain America: The First Avenger)
Following numerous failed attempts to sign up to help in the war, the sickly, skinny Steve Rogers is becoming disenchanted and confides in his friend Bucky Barnes. Overhearing Rogers' conversation with Barnes about wanting to help in the war and being impressed his enthusiasm, Dr. Abraham Erskine allows Rogers to enlist. Rogers is recruited in to the Scientific Strategic Reserve as part of a 'super-soldier' experiment under the supervision of Erskine, Colonel Chester Phillips and British agent Peggy Carter. Phillips is unconvinced by Erskine's claims that Rogers is the right person for the procedure, but relents after seeing Rogers commit an act of self-sacrificing bravery - he jumped on a fake grenade which very well could have been real. As brave, selfless and as admirable as it may have been, to jump on a grenade during a training exercise is questionable decision-making at best.