Spycicle: Helps me remain undetected by pyros.
Dead ringer: Helps me infiltrate the enemy base, and to make them paranoid even after their pyro checks an area.
Ambassador: It helps me deal with enemies from afar,I've handled snipers, engies. Once on Dustbowl, I was hiding by the first point after it fell, and saw a BLU heavy and medic. The medic had just gained a full uber. He performed the "Meet the Medic" taunt within my range. I can only imagine how that person was the moment they died.