Integration is very hard. You are taking a house built in the northeast with victorian design, shingle roof, and a mix of iron, copper, and plastic plumbing and asking it to be seamlessly integrated with a house built in Canada! 2. The people making decisions … for the integration process. By underestimating the challenges that integration of systems can create, TD may have lost customers due to the unexpected downtime that could have greatly inconvenienced many.