Well if you're drying them all the way, and then ironing, you'll never get the fabric smooth, so I can see why you'd try softener. I don't have experience with hard water, so that may change things, but my shirts started looking 10x better when I stopped putting them all the way through a dry cycle. If you do dry them all the way, or too far, mist the fabric with a spray bottle (use distilled water if you are picky, I don't bother), then roll the shirt up and if you have time put it in a plastic bag for a while to sort of steam itself damp. If not, just mist and roll or just mist, then iron. Another important step that I didn't know before reading it somewhere (maybe Martha Stewart?) is to allow the panel of fabric to cool for a few seconds without moving it, after ironing it out. That is, spread the fabric over the board, iron it (lengthwise strokes only lest you stretch the fabric out), and then let it sit for 5-10 seconds to allow the fibres to set flat, before moving to the next section.