There were times that everyone forgot how good of an actor Neal was. With a smile almost always at the ready, an eye twinkle any movie star would be proud of and enough easy confidence to make a politician jealous, Neal Caffery was very good at getting people to see what he wanted them to see.
But sometimes, Peter remembered that not all was well in the world; he remembered that Neal had spent too much time in supermax to come out unchanged. It didn't always show, but if Peter knew anyone (other than Elizabeth that is), it was Neal Caffery. He'd spent a good chunk of his time chasing and studying the conman, and the Neal that went in to prison was not the same one who came out again.
It was in the way Neal would sometimes wolf his food down if he wasn't paying attention enough to consciously slow down, or how he would try to never let himself walk down an alley or hallway alone. Large groups of people in enclosed spaces seemed to make him nervous, though Peter doubted anyone other than him could tell. Neal would go outside on any sunny day to eat lunch, even in the middle of winter when it was so cold Peter was convinced his brain would freeze, just to be able to feel the sun on his face and the wind in his hair.
Peter saw all of this, but never said anything. He saw how hard Neal worked to look normal, act normal. To make sure nobody saw past the delicately placed mask he wore all the time. He couldn't do anything about having put Neal away; he wasn't sorry about that. But he was sorry about what it had done to the other man. Neal was more like a rambunctious puppy sometimes than a criminal, and if pretending that prison had never happened is what it took for Neal to get through the day, Peter wouldn't take that from him.