O'Brien turned down a move to Portsmouth in the January transfer window - because of Owen Coyle.
O'Brien, a bit-part player with Bolton this year, said: "The new manager has been a breath of fresh air. The way he comes across in TV interviews is the way he acts.
"He's bubbly, has an infectious personality, appreciates me for what I can offer and gets the best out of us all.
"His philosophy is to encourage everybody because he reckons the best way to get stuff out of people is through positivity. Not all managers are like that, believe it or not.
"The fact I didn't leave in the transfer window tells you all you need to know about what I think of Owen.
"But the bottom line is that I will have to wait for an injury or suspension to get me back in the team."