What I find interesting about dinosaurs is what they lived alongside. Flora, fauna, and so on. There must've been some pretty nasty parasites that lived back then just as now. There were no grasses or flowers during most of the Mesozoic. Gymnosperms were the dominant form of plantlife at the time meaning no fruits, either. There were still loads of insects, even some pretty meaty ones that would've been the size of rats. Snakes, too, lived alongside them.

And there were even mammals large enough to have preyed upon dinosaurs. The largest mammals during the times that we've found fossils for would've been the size of wolverines, and we found them killing psittacosauruses in the fossil record. So there had to be larger mammals that we don't have fossils of. Maybe some that even got to the size of wolves or caracal cats.