unbelievably, strain may be properly meant. You're probable familiar the term "fight or flight." it is your frame's natural reaction to stress. When presented with a disturbing state of affairs, we both get aggressive, or run away as fast as we will inside the contrary route. Just photograph a grizzly bear with cubs and without cubs. With cubs, she'll tear into anything providing risk to her youngsters. With out cubs a noisy noise should make her run within the other route.