1. When I knew you in college, half the time we'd end up thinking/saying the same thing. It's not every day that happens.
2. When all is good, you can totally see the sparks behind your eyes.
3. Probably as a combination of 1 and observation, you pick up on certain things so that you don't always need things to be spelled out for you, especially when I don't want to spell them out. Cryptorchid is a prime example.