Most of us probably know that the word "dinosaur" didn't exist before the nineteenth century. Further, if you look at dictionaries before about the 1950's, "dragon" meant dinosaur. Dragons, dinosaurs, it's all the same thing. Some is based on truth; some is fictionalized. Some is based on stories handed down over generations; some is based on fossil observation. Whatever is true or real we don't always know, but either way dinosaurs have always captured our imaginations.
Natural curiosity has plenty of material to ponder over when it comes to extinct reptiles. The puzzle of figuring out what is what would be enough to keep our minds excited. But more than that, dinosaurs bring us to wonder what the past was like. We imagine these creatures and imagine what their behavior and lives were like and what kind of world they lived in.
Species are going extinct all the time, and the dinosaurs were no different. And when you don't have a live animal in front of you, what you can know for certain about it is limited. If I lived one or two hundred years ago and heard someone telling stories about a platypus or an ostrich or an anteater, I would have a hard time believing them. Actually, I still marvel at the fact that such a creature as a platypus exists (it looks like a beaver and has a duck bill and poisonous ankles, really?). Animals are pretty amazing.
If you were looking at, for instance, fossilized platypus bones it would be difficult to tell what a platypus was actually like alive. Paleontologists are always recategorizing dinosaur types and rearranging their skeletons and coming up with new info on their supposed behavior and diets. So how do we know that what we now "know" is pretty close to the truth if dinosaur facts 150 years ago were pretty different? We don't; we just enjoy the process of learning and imagining.
It's like we're trying to reclaim the past, reconnect with it. How were dinosaurs created so perfectly and splendidly that they continue to fascinate us even when they're dead? They're like diamonds, those little gems stuck in the ground for us to dig up and ogle over. The fossils, too, are there for us to dream and imagine and to study and learn. Little secret puzzles for us to play with.