Normal Parental concern is wanting to know where your child is generally going to be/with who at a given time of day/evening. Making sure that they are getting their school work done and trying their best at whatever they do, and keeping them as healthy and happy as possible, motivating them to discover themselves.
Too much concern would be putting video cameras all over their room/and even in their car, and pretty much anything that constitutes as "spying", especially when they are a teenager+young adult. This will break their trust in you, essentially shows them that they don't trust them to make smart choices, and that will make it all the more harder for the parent to get the teen to listen. Trying to control your child's life also falls under this category. It's paradoxical that parents tell their kids to be independent, yet raise them to be otherwise.
Having not enough concern would be a parent not openly communicating with their child/teen, not motivating them in any way, not praising their achievements, not evaluating failed attempts,not caring if/when they leave and when/if they come home that night, not caring to know where they are at all. Pretty much this shows the child that the parent doesn't care, and that behavior could wash off onto the child in the future.
Parental rights have definitely decreased. When I was a child, if one did something wrong, they could be spanked and it was not considered abuse. Now a days, that is considered abuse, so parents give their kids "time-out", which for some doesn't even feel like a punishment, since they are in the comfort of their bedrooms full of electronics and games. It's no wonder the younger kids misbehave so much. I believe that a good spanking can build up a child's character, and I am not talking about those that leave marks on the child, just enough so the child get's the idea of "don't do that again"
