"Intelligence and subtle humor"

He's a great guy, a real pleasure to work with. He's well-read and knowledgeable, able to hold a conversation on a wide range of topics and always notices important details. He has a keen mind: he thinks quickly, thinks deeply and interestingly, without being overly pretentious. I'd especially like to mention his humor: subtle, well-timed, and well-paced, the kind of joke that lifts the spirits rather than derails the conversation. He's easygoing and friendly, so every conversation leaves a positive impression.