What lens did you use? If you picked a single AF point, it can mean you're facing a problem with front-focusing lens and a simple calibration should help you. In all your shots your focus is clearly in front of your subject.
You can easily test for this using a tripod, picking a single AF point and observing your resulting photos. Also make sure you're testing with inanimate objects, so you rule out any human errors. For instance some slightly angled book is a good test subject. Try to focus on a specific letter/word and it has to be sharp. If it's not, you know you have to calibrate it. As you have 6D, you probably won't even need to visit a service center for that (you can adjust this from the menu in your camera).