well, gryffindor and slytherin are considered contrasting houses, but they both have great ambition. the lead difference between the two is their methods; a gryffindor prefers a valorous victory, meeting his enemies face to face and a slytherin rather be waiting, planning it out, and attacking her enemies when they are vulnerable: emotionally, physically, or socially. gryffindors are also fine with failing the first time, but have amazing perseverance and will try again; while slytherins make sure failure is never the outcome. this might be because a gryffindor doesn’t seem to care what society thinks of him, while a slytherin is very cautious about her appearance to others (whether or not she admits it), because she needs respect, or at least fear, from her peers.

they are very alike, but it’s kind of like having a warrior, ready to rush into battle, travelling with a thief, or assassin, who wants to stay in the dark and attack from a distance or while the enemy is asleep. this is probably why the two houses butt-heads a lot.