I find my towels get stiff and dense when I let them air dry (as opposed to soft and fluffy when I machine dry.) Am I doing something wrong or is this something people just get used to?
You should try "spin wash cycle" for 10 mins after washing (not sure about the translation, essorage in French - dewatering).
So you have the best of both worlds: Your towels air dry quickly, and are fluffy, you use far less energy than drying machine, and your towels / clothes are preserved.
I guess I can see the appeal of soft fluffy towels, but I actually prefer mine stiff. I can't justify or explain it, but ... I do. Sheets as well .. thick linen sheets, air-dried so they're kinda hard ... mmmm.
But I didn't have to get used to this, I just immediately preferred it.
I’ve heard that one can add white vinegar in the washing machine to soften the fabric, but so far I haven’t tried it.