Overly helpful store employees are just doing what they are told to do by their boss which is to ask customers every so often if they need help finding something or not.
But I do agree they are overly helpful which gets too annoying and I believe they should only have to ask the customer once if they need help if they see them looking for something.
But when you tell them no you're fine and don't need their help at the moment they should leave you alone and go help someone else.
I really hate overly helpful employees who seem to ask me too many times if I'm finding everything I need as it makes me feel uncomfortable and annoys the heck out of me.
It also makes me forget sometimes what I came into the store for.
I wish employees would be able to just leave the customers alone until they need help with something.
Maybe ask the customer once if they are finding everything they need but don't ask again unless the customer comes to you.