Can dentists tell when you’ve started to make a lot of effort with your teeth cleaning despite having bad teeth?

Due to being raised in a family where dental health wasn’t important and then spending most of my teens and early 20’s with awful mental health (never even kept up regular brushing and didn’t go to the dentist for 10 years) I have really bad teeth. The last 4 years or so I’ve been making the effort to keep up good dental hygiene and I’ve been replacing some metal fillings to white fillings. My teeth are pretty yellowed still and overall not looking great but i’ve had a lot of issues with rude judgmental dentists despite me explaining why. I recently moved to a new dentist and he praised my flossing and brushing and I couldn’t tell if he was just being nice because I over explained why I have bad teeth or you can genuinely tell.