Hughes hung up the boots last year with Hearts.
He told the Evening Chronicle: "He was fantastic and I really wish I had spent more time picking his brains and asking him more questions.
"It is one of the biggest things I regret. Not really appreciating the experience and the players he had worked with and the things he had done.
"Obviously I knew them and I knew who he was and what he had done but everything was the present at Newcastle and trying to do my job for him and impress him there and then.
"He is the type of manager who would have sat and told you about it all day and really give you his time.
"As much as I really appreciated him there is that side where I wish I had more time."