Of course you have to rely on sincerity rather than skills to get along with your friends and roommates. Since people are together, as a day, it makes sense to see each other's hearts for a long time. You just use skills, no matter how superb your skills are. Over time, there will always be exposure, but the real thing is that friendship has developed very well no matter when, and if you treat each other sincerely, the other party will also respond sincerely.