When I draw a straight wall or CAD line, it doesn't appear to be straight. The line appears jagged, or off angle, as shown in the image below.

What is causing this, and how can I stop it from occurring?
It is often important that objects be drawn at exact angles. This can be accomplished using Angle Snaps, which allow you to draw lines, walls, and other objects at specified Allowed Angles. Angle Snaps also affect the way objects rotate, the radius of arcs, and a variety of other operations.
If you have turned off Angle Snaps, your walls may appear jagged in floor plan view. Also, you may notice the Angle Snap Indicator
attached to your cursor indicating that angle snaps are turned off.
This can ultimately lead to room definition issues or problems with dimensions, so it is best to correct the file as soon as you notice the behavior.

This toolbar is docked to the right side of the program window if you are using the standard default toolbar configuration.
A blue border along with a small checkmark will display near the lower right of the icon when this tool is enabled.
from the menu on a Windows PC or Chief Architect> Preferences
on a Mac, and turn the feature on or off on the Snap Properties panel of the Preferences dialog. 
Once you have toggled Angle Snaps back on, you will still need to correct any walls or lines which have been drawn incorrectly by specifying a valid angle for the object.
tool, click to select the off angle wall.
