What makes a thiller a thriller?

Thrillers are determined thrillers generally by including fast pace, frequent action and hero's who over power the villains. Thrillers are also conventional for suspense, cliff hangers and red herrings which keep the audience locked in to the film and on their toes. Thrillers tend to be set in exotic place's such as deserts, polar regions or high seas. The main character/hero is traditionally a male who is in love with danger and has no fear but women have been increasingly becoming popular as the lead role in thrillers for example Sigourney Weaver's character Ripley in "Alien" (1979). The thriller genre normally goes hand in hand with the Mystery genre but in recent years thrillers have been interlinking with horror or psychological-horror and don't always have that happy ending for their main character and tend to make them less of a hero and more flawed so the audience can relate them them as real human beings and therefore be more engaged. So in thrillers influenced by film noir or tragedy the hero is often killed in the process of defeating the villain. The bourne films contain many conventions of thriller starting off with "The Bourne Identity" and carrying on through to the other two films "The Bourne Supremacy" and "The Bourne Ultimatum" directed by Paul Greengrass.The conventions it holds are that of the hero aspect with "Jason Bourne" as the hero and it also contains constant action with fast pace editing so fits nicely in the thriller genre but may also have a sub-genre of an adventure film. A thriller which takes on the more modern sub-genre of psychological horror is "Momento" which is directed by Christopher Nolan which I think personally is an amazing thriller and piece of work. "Momento" uses the fast pace editing through it's montages and flash backs which gives it the conventions of a thriller but it also has a twist on the whole hero aspect as through out most the film we believe he is a hero avenging his wife's death but we find out later that this doesn't turn out to be the case and he is his own villain so it also breaks thriller conventions in that case. Another well known thriller director is Alfred Hitchcock who directed thrillers such as "The Man Who Knew Too Much" (1934), "The 39 Steps" (1935), "Secret Agent" (1936) and of course his very famous "Psycho" (1960).