Re: yes, there's a difference ...
I took a class at uni with a guy who insisted on being called Shrimp. I refused to call him Shrimp. I wasn't friends with him and a nickname like that has a certain level of intimacy, at least in my opinion, and I didn't feel comfortable using it when I barely knew him.
He had an ordinary name like David or Daniel and I don't know why he didn't want us to use it.
* Ellen * Astrid * Eira * August * Isidore * Emmanuel *
but she wants to be sure 'cause you know sometimes words have two meanings