Discipline is a big thing for me, you have to respect the workplace and your team-mate.
I went to Borussia Dortmund on trial with a bag and some clothes, not knowing what my next move was going to be.
I've been to some great clubs, great people, watched them training, getting a different view on football, and really enjoyed it.
You have to make decisions that you think are right for the club. I also think that, in the dressing room, there should only ever be one voice and it's got to be the manager's.
But I don't pay much attention to outside influences. People can say what they want. I always try to focus on my own environment.
Criticism comes with Celtic. If you take it on board, it can make you ill, but if you think: 'No problem', it makes you really thick-skinned.
That's what drives me on, being frightened to fail. The past is in the past. I never think I'm safe.
I thrive on the pressure. I love it. I love the fear factor that goes with it. Perhaps it's strange, but that's just me.
I've never been spoon-fed for my whole career, I have always done it the hard way as a player and a manager.
It is hard to categorise every accolade you have won. Getting into the Hall of Fame is great. It is fantastic to be recognised by your own country. To be part of the history of our national game is simply humbling.
Every big moment has stresses and lessons that you take into your managerial career. You can pass it down to the lads who work under you. And everybody knows you handled it.
That churning in your stomach on the morning of a game, I've missed it. That adrenalin rush, I can't help getting involved. I can't watch myself on TV jumping around like a madman. But you know what, I wouldn't change any of it.
I've seen managers come in and lose the first game, you're on the back foot straight away.
I don't get Twitter or social media. I really don't understand it or read it. I see it as a distraction.
I never look at past results. It's about what happens now.
In Dortmund, the stadium is nearly full for the warm-up. They've always been there in their numbers, always backed the team.
I won't please everybody every minute of the day.
Any club that wins the European Cup gives it more credence.
Villa's history doesn't frighten me. Not at all. I respect it. I actually embrace it, because I've been through it. I know how difficult it is to win the European Cup.
I never think I'm safe. I always live in fear I will lose.
