October, I tended to do the same as pp regarding books. My son and I would lay in bed reading books and he would either drift off to sleep again or keep reading on his own while I drifted off.
And yes letting him cry it out will just teach him that you aren't there for him when he needs you
I really don't think we can blame bad behaviour on a loving mother tending to her child. Quite the opposite actually
I'll also add that the mental effects of letting a baby OR toddler cry it out may not present themselves for many years.