It's happened XD The Mythbusters tried it and the bulls actually walked around the shelves, trying not to bump into them. Only a couple things fell and broke. I'd look it up on Youtube but I'm on like ... the world's slowest computer right now >>;
It's still a bull. I doubt the store was designed to accommodate something of such size, so the likelihood of breakages are higher no matter how well mannered xD
They're actually pretty graceful creatures, but no matter how well mannered they might be, they're still huge. Huge is always going to be a problem in cramped spaces with fragile objects.
And not all have the right amount of space for a big animal like that to pass through. Even in the Mythbusters experiment, some shelves were knocked over. Not as many as they were expecting, no, but it happened, because you just can't get around having a size like that.