Remember that when dealing with some record agencies, government offices, churches and private businesses, helping you with your genealogy might not really be their job. County record offices maintain records, but if you don't know what you are looking for it makes it difficult for them to help you. Some offices may maintain old records, but their "real job" focuses on current day-to-day activities. Churches and private business maintain their records "privately," and really don't have to share information with you, even if great-grandma was a lifetime member or great-grandpa spend a "huge" amount there on his funeral.
Just a few thoughts. It doesn't mean that clerks have to be rude or impolite though!