I learned a laundry tip while I was in college because of my major (although it is called Polymer and Fiber Engineering now, it was called Textile Engineering when I was there). Here's the tip:
Never EVER use fabric softener (liquid or sheet) on towels of any kind or on infants' sleepwear.
Here is why:
* The same chemical reactions that occur to make your clothes soft and cozy also leave a coating of the softener on the towels and reduce their absorbency. Your towels, dish-drying cloths, bath cloths, etc lose that wonderful ability to absorb water and you really would just do better rolling around on the carpet in your bedroom to dry off. So anything that you own that you want to be absorbent, do not use fabric softeners on it.
*Most infant sleepwear is made to be flame-retardant. The chemicals in softeners kill this ability, making your child's sleepwear as flame-happy as all of the other consumables in your house. The same goes for infant bedding (sheets, comforters, etc), which also is made to resist (NOT PREVENT) burning. This is a good reason not to buy infant sleepwear second-hand if this is a concern to you. Also...older children's pjs are not required to be flame-retardant, so you're safe there.
So, although I do not do this, I know that it DOESN'T work for me. Since I know that it doesn't work for you either, I thought I would tell you. ;)
Update: By the way...obviously great minds think alike, because Heather had this post for her What Doesn't Work for Me post as well!