Why do two lines of text ignore spacing unless more than one line is between them and how to not make it happen?

I apologize if this is not right to post here but im not sure where to go with this one as i havent really found an answer myself.

See, heres the thing, as yall surely know when i hit enter on a line once it will not work, it has to be two.

Is that intentional, if so why?

how does one disable that?