Edited: I need to ask about the following sentence where I doubt whether both verbs make sense and can be used interchangeably or not:
1) Every year all people ............ in this square at Christmas and celebrate this day.
2) ............. all the staff in my room for an urgent meeting. (said the directing manager to one of his colleagues)
a) get together
b) gather together
For me, in both sentences, all the verbs work properly, naturally and interchangeably. I need your confirmation on my take.