Giggs admits his sleep dwindled to less than five hours a night as his time in charge wore on and tells of his anger after United lost at home to Sunderland in his second game in charge.
"I was upset after the game but the longer it's gone on since, I have just got angrier and angrier, slept less and less and just, you can't have it, you just can't have it," he revealed.
"If any of them want to come and see me and ask me why they're not playing then I'll tell them and I don't think they'll have a leg to stand on.
"I mean, I just, I was stood on the side against Sunderland just wishing I'd named myself as a substitute so I could something about it.
"I bet every manager thinks like that, but I'm in a position where I'm still playing and can still affect the game.
"For 20 years Sir Alex Ferguson used to say, 'Wait until all you lot are managers and you'll find out how hard it is to pick a team, to leave good players out', and I was just say there going: 'Yeah, yeah, yeah, whatever'.
"But it's like having your first baby.
"You can prep as much as you can, but until it comes down to actually living it day in, day out, you can never prepare for it.
"I was really, really down after that game and you know, that won't happen again.
"We prepared right, we knew that Sunderland were gonna be a tough team because they were on a good run, and you just pick a team and what I did was I picked a team that I thought could win the game and I trusted the players.
"But some of the players let me down and let themselves down. Maybe I was a little bit too soft."
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