The Swansea City manager is an unpopular figure at Vicarage Road having quit the club after a little over six months to take charge at Reading.
But that is now behind him and he is taking his Swans to the ground where they last tasted a league victory on the road – back in March.
He told Wales on Sunday: โIt was unfortunate the way it ended with Watford.
โMy gut feeling at the time was to leave, but there is no doubt, when I look back in hindsight that I shouldnโt have.
โI always wanted to go to a club that was going to give me a chance as a manager. Watford did that. They gave me the opportunity.
โI didnโt make a really good start there and the club was a bit broken.
โIt took a bit of time for my methods to get across and for us to get results, but I was able to pull it all back in together as a one-club mentality.
โI think that was my sadness. There were a couple of comments in the press which were obviously misconstrued and left me in a worse light than it actually was.
โThere was the disappointment of giving the supporters hope that they had someone in charge who was going to be in the job for two, three or four years to help them grow again.
โThey loved my style of football and the way we were playing. We were going from strength to strength, but then all of a sudden I went.
โThe fans probably felt I had let them down and I can totally understand that. I have met many Watford supporters and had many letters thanking me, but it didnโt fit well with some and I can understand their feelings.
โBut I wouldnโt have left for any other club than Reading, a club I knew well, where Iโd lived for 21 years, where my children were and it was a real heart pull on me.
โI actually had key people from within the club saying that I couldnโt pass this opportunity up. So I went with no regrets at the time. Then there was the backdrop with the comments which I didnโt make and that fuelled the supporters.
โBut I look back now and realise it wasnโt the right thing to do, even if it has made me a better manager.
โI didnโt go back there with Reading, but in the home game there was a lot of tension and I had a 24-hour bodyguard.
โI was told there was a threat against my life from the fans coming to the ground. I only found out on the Thursday before the game when the local police warned the club there was something happening so they brought in security.
โThatโs not me. Iโm a guy who works openly with people and the decision was a gut feeling at the time.
โBut, all that aside, I have nothing but great memories of Watford.โ