I'm pretty new to SolidWorks in compared to some, not quite sure how this problem managed to occur. Whenever i'm sketching a new part and dimension it after clicking to set the dimension it still has the line selected. So whenever i go to click another line instead of getting a dimension of the new line i get an angle or distance of the two. All i have to do is hit esc after each dimension, so its not a huge problem, but would like it fixed.
There was some new behavior a few releases ago where a dimension would automatically apply to a pre-selected sketch entity. To avoid it, make sure you don't have anything selected before starting the "Smart Dimension" feature.