To cause pain or to stop the flow or pattern of ur chakra those are the only two wayz to stop a genjutsu but u can not go out of RP and say I recongize its a genjutsu and stab myself u gotta say how u recongize it. Genjutsu is all about time, planning, and strategy if your not a skilled ninja that thinks things through then genjutsu is not for you. Being a sharingan user is not for you if you wont learn genjutsu. Genjutsu is a big part of the sharingan and uchihas. Now answer this question what is genjutsu.