good day dear friends,

I have a thing that bugs me at the moment: I have a collection of dots and I want them to be combined (through the midpoint.)

well i think this has to do with the following:

a. combining them - and linking them .. with lines (- from the midpoint [not necesary at the moment].)

but what bugs me is the fact that the line at the second dot is goes out to two sides - not only to one. See the image..

btw - ive added another image where we can see what happens.  

well the question is: why does the line divide into 2(!)  directions.

how can i stop this behavior.!=?

Either have snap to rotation centre enabled.

Or use the connector tool

I suggest...
    [Enable snapping]
        [Other points] [Object midpoints]
        [Nodes] [Cusp nodes]

To draw straight segments with the Pen tool [b], try [click-release] instead of [click-drag].

Also, this recent topic might help you.
https://inkscape.org/forums/questions/combining-dots-the-process-ends-up-with-the-creation-of-a-colored-field-duhhhh/

Hold the shift key when dragging the mouse - this will create corner nodes with one Bezier handle.