No one is surprised that the lion is considered a dangerous animal. As the king of the jungle and an apex predator, both animals and humans alike respect and are frightened of it.
Yes, they spend the majority of their time sleeping and appear lazy but don’t think that it is the large male lion with the massive mane that you need to be most afraid of. The female lioness is the talented hunter and will think nothing of mauling you alive if she is provoked or feels that her pride is in danger in any way. 250 dead humans every year is proof of this!