I don't buy Apple stuff so don't know anything about Apple stores -- but I've encountered it in other stores (usually ones that fancy themselves "high end" in some way).

It drive me crazy. It's bad enough to have to talk to a salesman when I wasn't seeking one, it's even worse when I tell that salesperson that I'm ready to buy something specific and then they waste both of our time trying to do anything other than take my money and give me the thing.

Those are stores I'm unlikely to return to.

This is different than when I want a salesperson to explain things to me. In that case, yes, please shower me with attention as long as they're one of the ones that are actually helpful rather than just constantly trying to sell.