hi guys, first time posting on here and needed your help. I have a puppy who is a rottie mixed with german shepherd and is 12 weeks old. He’s been really friendly with strangers and dogs. Let’s people pet him and likes to lick them all over. However today I was at a pets store and a women came up and asked if she could pet him and obviously I let her. She seemed like she knew what she was doing. However she started to tell him to sit and lay (obviously we’ve taught him that already). She started telling us what not to do and do and my pup grabbed something from underneath an aisle which was paper and started chewing it. She told him to take it out, like literally forcing him to. Saying “we should of taught him to leave it”. And she grabbed it out of his mouth and said leave it and he sat down. But as soon as she tried to pet him again he bit her lightly. Like more of a playful way rather than hard. (I know the difference). Obviously I told him not to and held him back and she was saying how “if it was my dog I would of literally put him down on the floor”. I didn’t know how to react because he hasn’t done that before. But I felt like I did something wrong, didn’t give him the right training. And felt so guilty while taking him back home. I just wanted tips from you guys to prevent this from happening again. Has this happened to any of you guys before? How did you fix it?