Humans and animals tend to blame and punish others (even those who are not responsible for the happenings) when things go wrong:
In one experiment, two pigeons were placed in a cage. One of them was tethered to the back of the cage while the other was free to run about as it wished. Every 30 seconds, a hopper would provide a small amount of food (a fixed interval schedule, as described earlier). The free pigeon could reach the food but the tethered one could not, and the free pigeon happily ate all the food every time. After an hour or so of this, the hopper stops providing food. The free pigeon continues to check the hopper every 30 seconds for a while, but when it’s clear that the food isn’t coming, it will go to the back of the cage and beat up the other pigeon. Now, the interesting thing is that the tethered pigeon has never eaten the food and the free pigeon has no reason to think the other is responsible for the food stopping. The frustration is irrational, but real nonetheless.
New expectation/standard matters a lot:
A related phenomenon, called “behavioral contrast," occurs in chimpanzees, among other species. A chimpanzee is doing a simple task such as pulling a lever and is being rewarded with pieces of lettuce, which they like to eat. After doing this for a while, one pull is rewarded with a grape, which they really love to eat. On the next pull, the chimp is given lettuce again and they get very upset, throwing the lettuce at the experimenter. They were perfectly happy with lettuce before, but the presentation of the grape creates new expectations and when those expectations aren’t met, frustration and anger invariably results.
Read more here.