What some people don't realise it that the yawing is made even more so by the fact that the increase in power in a big engine is not linear.
If it was linear, you might only get say continuous 10% difference in thrust. But once the power levers are set to TO thrust, you might get negligible thrust increase for a few seconds then around 80% of the thrust kicks in in only 2 seconds. So if the second engine is 2 seconds behind the first for whatever reason, it's a huge - immediate - difference.