We bought a house last year in what was a moderately complex transaction. What we were trying to do was purchase a "new" home (it was actually 2 years old, but had been the model home in a neighborhood so it hadn't actually been lived in) and, at the same time, build a detached garage on the property. While this seems simple, actually doing this in a way that doesn't involve multiple loans is surprisingly complex.
In the end, it would be a low-risk, vanilla, 30 year conventional mortgage, and we had enough cash for a 20% down payment. It just required some complexity to set up.
Not surprisingly, most major banks wouldn't even try to help us once we explained what we were trying to do. It didn't fit any "profile" they had and the "system" was unable to let them continue. We lost count of the number of times we were told that a "system" prevented them from doing something.
So we went to a local bank - only one location, right in the middle of town. We sat down with an older guy who's probably been making loans in this town his entire life. The president of the bank came over and talked to us, and congratulated us on our coming addition to the family (my wife was 7 months' along at the time, so very clearly pregnant).
After talking with us for an hour or so, before having even filled out any paperwork or pulled any credit, they were confident they could help us. They were even more happy once credit had been pulled, and offered us rates lower than any of the big banks were offering at the time. What we ended up doing was writing a 4-month construction loan for the purchase price of the house plus the cost of constructing the garage. A few months later, when the garage was completed, we closed the loan and had a single mortgage for the whole property.
So after that experience, I've started recommending my friends and family stay away from big banks and work with local banks and credit unions. Big banks may be great for the convenience factor of having branches everywhere, but they fail hard when it comes time to do anything remotely out of the ordinary.