When customers come to you for a tech support issue or because they need troubleshooting assistance, they want to be able to trust that you’ll offer expert advice and instruction. One of the biggest mistakes you can make when providing IT customer service is to act condescending, or make your customer feel like they're responsible for the problem. You can find ways to offer tech support and assistance while being friendly and kind to the customer. Here are some of the most common customer service mistakes you should avoid when working at an IT help desk or tech support line.