How many of you found those call center service helpful?

I have had some bad experiences with some customer service call centers. I have also had some really good experiences with some. Alot of times, though, the bad service will outweigh the good service. For example, say you call Company A and have a really great experience. You have an additional reason to call 2 weeks later and you have a very bad experience. Most of the time you are only going to remember how bad the last representative was when you called. One representative can ruin a customer's experience for an entire company. Some companies pride themselves on having very good customer service, and when I have called these companies, it shows.