I acquired a 3 month old walker about 2 weeks ago and the obedience training has really been coming along good. I've been taking him on woods walks at least 5 times a week; he does really good the first half of the walk but then when we turn around he acts totally different; he pulls a lot more and if I'd let him he'd run back to the truck. Why does he do this? Why's he so eager to get back? Thanks for any insight.