When someone initiates contact especially via a broker counter and counter high. They are more scared of you not agreeing to sell the name than you are of them being turned off by your counter.
If you have fear you will never make a penny in this business, you will end up playing chicken on the good names you have, and with the bad names well you will end up renewing as you will fear maybe this time someone will buy it. Domang will end up being a zero sum game for you or worse.
As a domainer the minute someone contacts you about a domain they confirmed you have prime property. After all 99.9999% of domains will never get any interest at all in their domains, hence the massive drops daily.
If they go ahead and make an offer in the high XXX or low XXXX then surely you have good prime property. The idea that they can easily go grab another name is nonsense. Sure they can always get alternatives but they are in love with your name for whatever reasons, even if it might not make sense to you.
Its like dating, you see people chasing someone and doing all kind of silly things trying to go out with or stay in a relationship with them when in fact from your prospective they have so many better options. You cannot and will not always be able to pinpoint why someone is in love with your name, but when it happens you must be confident that they need you more than you need them and start believing 100% that your domain is highly valuable.
Learn to have extreme patience and do not email them unless they ask something. Some of the high XX,XXX + names take many months from start to finish, lots of that time is spent just sitting and waiting. Initiating contact can only destroy the sale.