I installed a new lavatory sink drain . All plastic, made up very hand tight but 3 of the 4 threaded connections have a couple drops of water. I lined up all connections before tightening any. I have put in about 8 new sinks over the years and never had this happen. I can tighten more with channel-locks but I am concerned with breaking the plastic. These are all compression or flare connections so should not need pipe dope. What did I miss ?