At least allow us to flip the connection of the offset line. The dialog box has the button but is always grayed out. That is the biggest headache I have with offset lines. The only way I have found to get it right the first time is to select the end of an axis (not easy with all axis showing in a large assembly).
I can usually get the 30 degree offset line to snap into place if I move the correct end first.
For reference to other. The direction of the explode line is depending on which side of the axis you click.
So on the example above, when you click on the bottom end of the axis of the first bolt, the explode line goes down. When you click on the upper side of the axis of the left washer, the explode line goes upwards.
The explode line is easier to create correctly when an axis is used. However. when using a cylindrical surface, as was done in the example, we don't appear to have any control over the direction the line takes. Orientation of the model, and where all of the clicks are placed may have some impact on the direction of the explode line but I have not been able to come up with a definitive process to get the desired outcome.