Injecting subjective, modern-day judgements on ancient civilizations like calling them "bloodthirsty" is just bad-mouthing ancient civilizations and not objective historically. If your goal is to look at ancient civilizations and just insult them or consider them inferior because their customs are denounced by your own civilization, you will have a hard time understanding history.
To correct Swamp Yankees answer, Aztecs were not "like" Mayans, they were Mayans. The Aztecs were a Mayan people that invaded and conquered central Mexico. Like all Mayans they believed that the god of the Sun needed to be propitiated by the sacrifice of human blood. Mayans often cut themselves and drained the blood into bowls for the purpose of sacrificing their own blood. One type of blooding involved thorns threaded on twine which they would pull through their own tongues to draw blood.
When the Mayans conquered the Mexicans they sacrificed as many as they could to the Sun, sometimes in large ceremonies where hundreds or thousands of prisoners had their hearts cut out and their blood drained in sacrifice to the sun.
As far as violence is concerned, the Aztecs were "violent" and were proud of it. Being a warrior was a privileged position in society and the Mexicans held the Aztecs in absolute dread. Not only the Aztecs but many of the surrounding Mexican tribes were very warlike and violent. For example, when Cortes was marching to Tenochtitlan (Mexico City), his force was attacked by a tribe called the Tlaxcalans who were especially warlike. In one battle, these men kept attacking the Spaniards until the men of Cortes were fighting in a pool of blood that came up to their knees and the number of bodies was in the thousands.
One of Cortes' lieutenants, Bernal Díaz del Castillo, wrote about a book about the march to Tenochtitlan which describes in detail many of the Aztecs and Mexicans whom they encountered, so if you are interested in their attitudes, you might read his book.