Response to 18 Everyday Products You’ve Been Using Wrong:
#12 Tying cords into a knot is wrong. The part of a cord that gets the most stress is right around the plugs (hence the extra thick, flexible plastic to reinforce it). Tying it in a knot puts constant stress on that part, allows it flex around as tension is placed or released on it, causes the internal wires to twist and can kink the wires (which both weakens the wire and can decrease conductivity). Do NOT tie you wires in a knot.