For the most part, us saying look into their eyes is yet another issue of a human anthropomorphizing an animal. We don't actually have a clear way to tell what the reptile is thinking or feeling, as the expressions are truly alien to us, being a completely different species. I've noticed that the best way (or what I feel is the best way) to tell the reptiles mood is to watch their body language.
When mine is startled, his movements are abrupt and he keeps one eye fixed... I attribute that to being startled and cautious, though it could be something completely different. Closing their eyes could be them protecting their eyes from harm.
Either way, thats part of the fun... guessing what sort of primitive thoughts are going through their reptillian brain. So long as the Beardie has everything it needs to survive and be at peek health, I imagine it's quite content, and it does seem to learn when food is around, so it has some cognitive abilities.