Dinosaurs are not bad by themselves. They keep the little guy entertained for hours and he loves playing with them. And, he has about a million of them.
What sucks about dinosaurs is that there's a trillion different kinds with all sorts of weird hard-to-pronounce names. And that little guy must know the name of EVERY SINGLE ONE.
Ok. I know a couple different dinosaur names, but when they start to deviate from the main 5 I know (brontosaurus, T-rex, stegosaurus, pterodactyl, triceratops), I have no idea what they are. And that little guy is not impressed.
Ok, so half the dinosaurs we call "jumping dinosaurs" and the other half are "long neck dinosaurs" and some of them are "open mouth dinosaurs." Or they simply get a new name each time they're played with and I pray that the little guy doesn't remember what I called them the last time.
And that's why dinosaurs are annoying -- their names are just too hard to remember. I guess I'm not cut out to be a paleontologist.
(Also, stepping on dinosaurs or accidentally getting hit in the face with one is annoying, but that's a whole other story.)