"General Longstreet entirely misconceived his orders and instead of marching straight down Nine Mile Road massing in front of G.W. Smith, he crosses over to the Williamsburg Road, to get behind D. H. Hill. Of course he would not have done it had he not conceived himself ordered to do it."
Source: Military Memoirs of a Confederate
Commentary
At Seven Pines, Joseph E. Johnston envisioned a plan which Longstreet himself said "was so simple that it was thought impossible for any one to go dangerously wrong." However, as history has told us, almost everything went wrong.
Johnston's orders to Longstreet were verbal, placing him in command of the wing created by Huger's and D.H. Hill's divisions as well as his own, but Johnston also issued written orders to both of those commanders; however, those orders seem imprecise. Longstreet never accepted any responsibility for his failures at Seven Pines, mostly due to the fact that what he did he felt he had been ordered to do as comments from Sorrel and other indicate. However, as commander of the wing, Longstreet must bear some responsibility.
Longstreet marched his division down the wrong road and in the wrong direction causing an insurmountable delay. He was further hampered by a sudden storm that had broken the night before, leaving the roads muddy and many of the once narrow streams almost impassable in places. Because of this delay, Huger and Smith were unable to coordinate their attacks as had been planned.
E. P. Alexander's comments regarding Longstreet's actions: