Easily the most unwilling member of Team Voltron at first, Hunk was almost literally dragged into the whole event. Or tricked depending on how you looked at it. And though he was up for helping at first, he often questioned why he was there, and wondered many times, both quietly and out loud, whether he could go home.
Hunk's real turning point was in the Balmera mini-saga in season 01, where he found out first hand about the oppression the Garra empire was enforcing on beings across the universe. Once he saw the sadness of their situation, Hunk completely changed, and became a much more reliable teammate.
The Yellow Lion is his vehicles, and it's the most heavy plated armor wise of the set, allowing him to take blows for others and not feel as much effects.
Despite his goofy, and near always hungry, attiude, Hunk is really helpful when he wants to be. He's actually a good mechanic, often offering up solutions even Pidge didn't think up. Though he does still get scared a lot, Hunk is fully a part of Team Voltron now no matter what.