More can always be said, but check these threads with answers from /u/ParkSungJun, /u/kieslowskifan, and /u/Lubyak
https://www.reddit.com/r/AskHistorians/comments/1v40f1/what_accounts_for_the_extreme_interservice/
https://www.reddit.com/r/AskHistorians/comments/n2wp5o/how_bad_was_the_interservice_rivalry_in_the/