What you are doing by knitting through the back loop is twisting your stitches. You should be "untwisting" them on the next row..if you're not then all your knit stitches are twisted. This isn't a problem if you are happy with the way it looks. The problem when you do it all the time though is that it can affect your pattern. I don't know exactly all the changes you'll have to make to patterns, but here are some websites that might help.