It was long clear to me that he was troubled and had issues dealing with his success as to how it related to his unhappiness. Seemed to think that even though he had what many people would consider to be everything that one day something would catch up to him or that if he wasn't "happy" that it was somehow a failing on his part. You can see some similar threads in the lives of other artists who have committed suicide as well, some with more public fights with depression than others. To me his struggle always felt pretty overt if you watched him closely.
Bourdain's relatability, openness, intelligence, and broad decency shined through his work in a way that made him approachable to a broader audience than most. He made us look at incredible things, terrible things, and confusing things. He could be funny without demeaning, questioning without being insulting, and transfer a sense of wonder that is sorely lacking in daily life. Rare gifts which make the loss all the more painful.
He took millions of Americans out into the world. The real world full of real people we got to meet, not the world of guide books or sanitized TV travelogues. For that we should be grateful.