It's pretty likely you've found this kind of "advice" when you're in a low mood/crisis/etc. "You're focusing too much on negative aspects and blind to the joyful, positive things on life".

Thing is, what if you aren't actually blind on them? What if you can keep in mind the joy of, say, eating fresh fruit, getting a nice grade, watching a quality show, feeling the warmth of a person you care about, yet... even when you're in the middle of them you just think it doesn't really worths that much?

"You're responsible to build such a value onto them", "That's the part where you're being blind, in fact"... and what if has nothing to do with the values I put on them but I'm just hurt enough and tired? For example, I can go dive and delight myself watching the coral reefs while dying out of high pressure and lack of oxygen, yet there's this annoying voice telling me "it's all in your mind, you should value more this beautiful chance of seeing coral reefs that are going to disappear thanks to climate change"...

Don't know about you people, but when I say I'm tired and overwhelmed and I'm told such an answer like "you're not viewing things and your life in the correct way" I can't help but getting more frustrated (not against me but the answer I just heard), depressed than before. Sorry about the rant, but I'm emotionally exhausted of facing this, and I've given up on talking to most of people for being afraid to hear this again. Not because it's widely repeated makes it true, and I'm sure there are alternatives for handling this kind of moments.