Nothing looks more stressed than someone trying hard to look chill.

Effortlessness cannot be performed, because the performance is itself the effort and it shows around the edges. People read the strain rather than the pose, and the gap is more visible from outside than anyone believes. Trying to seem relaxed is a more tiring job than being honest.

Let yourself be visibly interested, visibly nervous, visibly trying at something. It costs less than the management, and people generally respond better to it than to the smooth version. The ones worth your time were never impressed by indifference anyway.