I worked phone support in an ISP for awhile, back in the mid 1990s. One call I got is etched indelibly in my mind... This guy was just... SLOW. It was clear he was trying - very hard - to understand what I was telling him, but it was just painful..
I had to explain things ten different ways, speak slowly, and repeat myself over and over again, to get him walked through setting up his DUN so he could get connected.. It took me almost two hours for what was typically a 10-15 minute process.
When he /finally/ got connected, he was ecstatic. And said in a completely deadpan manner "Thank you so much for being so patient with me. I know it was hard. You'll have to excuse me for being so slow, though. My parents were related."
I *barely* made it off the phone before I completely lost it, and had to be helped out of the calling area to keep my uncontrolled laughter from impacting other techs...