Steve wasn't unfriendly by any stretch, especially now that he was over the worst of his time-jump adjustment. Since he didn't know what to expect, he looked instead for women who looked at him for more than a few seconds.
Aha. The smile was instantaneous, and oh wasn't he going to be embarrassed if he was wrong, but it seemed like the kind of risk worth taking. Jean had been kind and he didn't want her to feel unwelcome.