Although I'm not in either demographic you're soliciting an answer from I believe each person has their own definition of "needy".
I had a friend who once told his girlfriend: "You see me when you see me." Essentially her wanting to know or plan for anything was a sign of "neediness" to him.
Sometimes (expecting) to be shown some consideration and respect are viewed as signs of being needy to others. Nevertheless every healthy person has "boundaries" and "deal breakers".
Examples might include if you're running late or won't make it but you fail to notify your mate, "falling off the grid" for several hours or days, being with someone who places a lot of value on birthdays, holidays, and spending romantic time together while you personally feel like you could do without all that pomp and circumstance.
Those are all examples of people who simply may not be "right" for one another or they have different ideas of what a relationship should be like. Odds are neither person will or wants to change.
Sometimes when people notice a "change" in behavior it alarms them or raises "red flags". Lets say in the beginning you were all over them and doing various romantic gestures to woo & impress them and then a couple of months down the road you slack off with those activities. While you may consider that to be "normal" your mate may start to believe your feelings for them have changed. They may believe they love you more than you love them.....etc
This often causes jealousy and insecurity.
On the other hand if you're with someone who needs constant reassurance that you are "into them" and whatever you do or say is never enough than in my opinion you're with a "needy" person.
The kind of person who will call you in fifteen minutes if you haven't responded to a text or they don't have a social life outside of you can make you feel smothered as well. It's almost one step away from being a "fatal attraction" scenario.
If you feel someone truly is "needy" RUN!
They'll drain the life out of you!
Odds are anyone who is like this can't believe someone loves or cares about them. They probably have been betrayed and disappointed by parents, family, friends, and lovers several times. They have become preoccupied with making sure it doesn't happen again. They need you to jump through hoops to prove your love over and over again or else they will blow up.
"Anger is the Mask that Hurt wears."