7They're willing to dabble in dangerous technology that could destroy them
Tony has never shied away from putting his own life in danger when it came to his inventions. He was willing to place a radically new source of energy in his own chest to save his life in the first film. Every time Tony puts on a new Iron Man
armor, he is trusting his life to an untested piece of tech that could easily backfire and take his life.
Thanos is willing to go to any lengths to possess the power of the Infinity Stones, even though no one else before him has ever managed to do so and there is no telling what the stones would do to the man who brings them together. Where other people are afraid to handle even one stone at a time, Thanos goes after all six because he believes he needs them to complete his mission.