fickle human behaviour 1-its not me-its you

Isn't it funny how as human beings we inteprete everything based on our shallow perceptions?
For example-who is a stalker? Actually-what characteristics does a stalker have?
They stalk you-duh! Follow you around-know everything about you? Obsessed?
Characteristics of a girlfriend-no?
So she doesn't literally follow you around, but she's always in ur pocket- a text or phone call away to explain why you are changing your plans for the day-she knows where you are-she knows what you like-what you don't like-chances are she knows what you had for dinner last night-yes maybe you WANT her to know these things-but she still has stalker traits
Or the day you met a guy that you thought was sooo hot!
The next day he calls you once and then twice and then again and again-and omg-hes so interesting and funny and cool and attentive
But you meet this guy and give him your number out of maybe pity
He calls-you ignore
He calls again-you pick up and pretend you were in the bathroom before-then proceed to pretend that you are enjoying the conversation
When he calls you again-he is a stalker
Ps-he hasn't even called half the number of times as hot guy
Or your girlfriend-you break up-you agree to stay friends
She's your ex now-she calls a few times or says hi when she sees you online
'Omg-my ex keeps bugging me'
My point-if you haven't gotten it by now is that if someone changes-and you remain the same-why are you left looking like the crazy person that can't take a hint?
What happens when the exact same things you used to do mean something else because the other person changed?