I unconsciously described myself as someone who love exploring different fields, therefore diving into science, playing with research...
The interviewer was impressed by the words "playing" and "PhD".
Yes, it certainly isn't an "all-happy" experience, but if one is passionate, one must find some "fun" in it.
If you're passionate in what you're doing, you'd just enjoy it as holidays.
This strikes him again.
He said, that's a mature thought.
Well, perhaps I'm just too much influenced by "You don't need a vacation when there's nothing to escape from." (Everything is sound, Jason Mraz)