I have, on more than one occation, heard a sailor criticise a new sailor for too many mooring lines being attached.
There is NOTHING wrong with extra lines and everything wrong with too little. Be reasonable with your lines but also always think about “what happens if this line breaks” what will be the result and time to fix it. If its critical and there is only one, perhaps you should double up?
There can also be benefit in adding lines that share and adjust the load, a line to the dock side bow will stop the boat being pulled backward, but will also pull the boat onto the dock with a wind from the front. Another line to the opposite bow will add extra backward protection, BUT will also tend to put pressure on the bow and pull the stern off a little, with the same wind, i.e. help balance the boat.