One place I don't bring him is into the computer lab where the water bubbler is. I used to bring him in, but I didn't want his presence to bother the students using the lab, so I spent some time teaching him to do long down-stays in the hallway. I put him in a chair at first to "anchor" him, since otherwise he'd break his stay when I went out of sight. After some practice with that, he graduated to down-stays on the floor.
A couple of times, though, he broke his stays and went into the lab, always because one of my student workers called to him in a high-pitched, squealing voice. I found myself getting unreasonably mad at him for this, even though I should've been scolding my student workers instead. But since a) there are a ton of them, and it's easier to train one dog than dozens of students, and b) I want him to be able to hold a stay despite squealing, and c) I want him to understand the concept of "don't come into the lab", not just "stay where I put you," and, most importantly, d) I do not want to get mad at my dog, especially for expecting him to do something I haven't taught him to do, I decided I needed a new training plan.
So I did a bit of boundary training. I took him to the lab doorway. I walked in, leaving him waiting outside. I released him, then clicked before he could enter the lab and tossed a treat behind him. He ate it and approached again, and again I clicked before his feet crossed the threshold and tossed the treat behind him. We played this game for a while, with me gradually increasing the distractions and resetting him when he crossed the boundary. He grasped it pretty quickly, although we spent another handful of sessions proofing the behavior so that he understood that he is not supposed to cross the threshold no matter what. He's not 100% there, but he's pretty darned good at this point.
I am sad that I got grumpy with him, but I am pleased that I managed to nip it in the bud and teach him what I actually did want him to do. (It makes me more sympathetic to my clients, too!)