Is withdrawing from two courses in my PhD bad for my future? I am a 2nd year PhD student. So far, I've taken 5 courses, 3 of which I got A and the other two I withdrew from. The reason was mainly it was not until the 6th session that I understood those two courses were not particularly relavant and helpful towards my thesis. My question is how bad is my situation regarding gettting a post doc, faculty position, or a position in industry, in the future?
For postdoc and position in the industry, it will not cause any problem. 
However, faculty positions depend on grants, and commitees pick people who are able to obtain fund grants, and publish papers. It is unlikely they will care about your grades.