Surfing Through "Lost"

I don't know about you, but after being attacked by The Others, a series of abductions (especially little kids), bizarre phenomenon like a sentient black cloud, a Doomsday device and other horrors, my natural feelings of openness and trust would be running a little...low. So why does Jack just assume some guy who pops up out of the woods and claims to be a wealthy balloonist who just happened to crash land on their mysterious island is in fact, telling the truth? I'm not saying Jack should be gung-ho about torture, but surely he'd be a little, I don't know, SUSPICIOUS. And why does everyone act so obtuse? The French woman finds Sayid and says, "Follow me," and it's pulling teeth to get her to say what's up. "How much farther?" asks Sayid. "Not far," she says enigmatically. Sayid does the same thing with Locke, waking him up out of a deep sleep and barking, "Follow me." Doesn't anyone ever consider just explaining themselves? And Jack, try to remember what your parents said: don't talk to strangers.