If I walk into a B&M shop, and even before i have a time to look what they sell, I am accosted by several members of their staff trying to "help", i am out of there....

In general, I would rather have someone ask if I need assistance than not ask. It's common courtesy as a staff member to try and be the most helpful that you can. A good way of doing that is knowing what they're looking for and that comes about by asking.