A girlfriend of mine used to say, when talking about an ex of hers that "ele não me dava valor." At the time, I thought she was saying that the guy "didn't give her money" ;-). And that may have been true, but not at all what she was saying! Let's review...
"Dar valor" to someone (or something) is to "not take them (it) FOR GRANTED.
*You can also say "tomar por garantido" but, this isn't used very much.
Literally, it's "to give value"
> Você não deu valor ao meu amor. = You took my love for granted.
> Eu não dava valor para muitas coisas da vida. Hoje sou outra pessoa. = I didn't used to value much in life. Today I'm another person.
> Eu achei que ela sempre estaria por perto para cuidar de mím. Eu nunca a valorizei. = I always thought she would be here for me. I took her for granted.
Dou valor a pessoa errada!