There are many ways for people, friends, and family members to address each other, each with its own nuanced Subtext for that particular relationship. This often factors in and includes such things as age, respect, social station, and gender.
So when a son calls his dad by first name, or a "friend" will only ever address you as "Hey, you! Yeah, you," people take notice... and offense.
There are many, many variations, but the general gist of Hey You is that someone deliberately calls another that deserves respect by first name, an insult, wrong gender, wrong honorifics, wrong pronouns, the wrong name altogether, or just plain "you".
A change in Hey You can serve lots of purposes other than establishing a disdainful relationship. A Deadpan Snarker or The Nicknamer suddenly calling the hero by name is a sign of hard-earned respect or seriously dire circumstances, likewise a boy calling his stepfather "Dad", or a drop in formality when Doctor Pretentious insists you call her Jane. Or the reverse, if Jane insists on "Doctor Pretentious".
One particularly odd subtrope is that parents, especially those in cartoons, often do not have names. People are forced to either call them by last name, or "Timmy's Mom" note .
The trope also comes to play in video games where you have multiple playable characters. Why bother altering every NPC's dialogue to address each character by name when you can have all dialogue just call every player character "you" and be done with it? Although a lot of games avert this with Hello, [Insert Name Here].
Calling Parents by Their Name is a subtrope for the specific example of a person addressing a parent, showing either a more casual, non-parent/child relationship, or just disrespect. See also Only Known by Their Nickname and Race-Name Basis. Not to be confused with the "You!" Exclamation. Or "Hey, You!" Haymaker. Compare Terms of Endangerment. Not to be confused with Hey, Wait!.
