Where two or more cars come together. Due to the speed and delicate construction of F1F1 is the pinnacle of open wheel, single seater car racing and arguably the highest level of any motorsport globally.... There's more... cars, most contact will result in, reduced performance, damage requiring an unscheduled pitstop or early retirement.
While all contact should be avoided, the nature of the sport is such that cars will come together from time to time. The worst scenario for a team is where their two cars contact and are forced to retire.