I don't know what it was about yesterday, but many customers seemed to not hear me when I greeted them with my friendly and non-pressuring "Hello!". Perhaps it was my pitch or volume or all the mesmerizing merchandise around them.
When I think that someone hasn't heard me, I usually wait a few more seconds for them to adjust to their surroundings and then try again. Sometimes it seems like they might be purposely ignoring because they don't want to be "sold" anything, and in those cases, I usually leave them alone until they are near desperate for help. I'm busy too you know.