I read Max Hastings book "Armageddon", about the last year of the War recently, and it opened my eyes to several aspects of the relationship between the allies which had hitherto passed me by.
The politics and squabbling amongst allied commanders did few of them any credit, with Montgomery a serial offender, and none emerging with entirely clean hands. Market garden was one of a series of what might be called unforced errors which cost lives, and in some cases prolonged the war.
A particularly pointed allegation from the book which I had not heard before is that Bomber Harris ignored direct orders to attack German oil production facilities, preferring to continue attacks on German cities, and it was only his public profile which prevented him from being removed.