Investment like playing a game golf. It will be a wishful thought that you can play hole-in-one in all 18 holes, unless you are "Dear Leader" Kim Jong-il. You may and you will make mistake in every hole shot, but the overall score after 18 holes is the most important than you could play brilliant one or a few hole-in-one in the game.
Realising making loss is part of the "normal return" of investment, trying to make less loss and make less mistake will make you a better investor than the average in the end.