I'll second all the anecdotes on this page plus add that I often won't even enter stores, especially small ones, if I judge it likely there will be too many "vultures".

I don't begrudge retail workers, really - I suppose they have a job to do. But geeze I wish they'd be more intelligent about whom they bother, and when. If I have not made eye contact beyond the initial "hello", then I probably do not need or want to be "helped" and following me around proffering same just makes me feel uncomfortable.