Main for ME1: Paragon, Spacer, War Hero, Vanguard. She always thought that all fame as "hero" and "savour" is undeserved - Shepard tried her best to save everyone she might save, but she undersands that if circumstances were different, she would very likely end as Butcher of Torfan. Tactical view and planning for future always were prior compared to emotions. Emotions, as well as displaying them, are just tools to rise a morale. So she tries her best to achieve everything while luck is on her side and "tactically correct" and "loved by crowd" works in same direction, understanding - and afraiding - the time when sacrifices should be made will arrive.
Main for ME2: Renegade, Spacer, Ruthless, Infiltrator. As a child from military family, she never was close to anyone - to family where one of the parents always was on risky assignment and another was all in engineering ships, not to friends which changed with every moving on another space station, neither to Alliance which only promised happy life to colonists and soldiers and really did nothing. Own people for her are nothing more than chess figures, and it doesn't matter how many figures will be lost while you win parties.