The first mass effect is my favorite, the other two are massively generic and overrated, it had a generic shooting mechanic , almost like a shooter than an RPG, very forgettable battles , that are just hordes and hordes of enemies, also filled with pointless and "Try too hard" emotional scenes, and love scenes, it all felt like a joke compared to the first one , where bioware actually tried to be original.
tl;dr might as well just play the first game and skip the rest.