Well yeah, subtlety is a big part of it. There's a major difference between a scene that's meant to evoke a specific reaction and one that just hammers it home with a two by four upside the head. I mean look:

"I have terrible news," said Mulder, hanging his head in sorrow. "Really bad. I've... I've got CANCER."

"Oh no!" exclaimed Scully. "Not cancer! Not after Skinner's been permanently crippled in a completely unexpected tractor accident after finding out he had a winning lottery ticket!"

"Yes. Cancer. But that's not all." Mulder took a deep breath, running his long fingers through his magnificent locks. "Your dog just died, Scully. I didn't want to tell you, but he ate one of my porno tapes and choked on the plastic."

Scully tried not to imagine how Queeqeg's last moments must've been, his furry little legs twitching frantically as he gasped for air. Her eyes filled with unshed tears, and a dull ache throbbed in the pit of her stomach.

Etc. etc. Writing that's really obvious about trying to wring an emotional response from the reader is bad writing. If it's good, then you're probably not going to notice that hey, someone's trying to make me cry! You'll just cry.