A player's mentality is very important. The five or 10 per cent where they're not focused because of wanting to go somewhere is enough for them to haul off their quality. It impacts on everything. So, as a board and manager, you have to make a decision.
I look at Rafa Benitez in his time at Liverpool, he had difficult periods and the same goes for Brendan Rodgers in the same job now. These difficult periods come and you have to accept that.
If you've had a bad experience with an agent, you have to move past it. You are bound to want a player at some stage who is represented by this guy and you will have to try to work around the personality of the agent. You tend to work out what makes them tick, what they respond to. You have to have tactical plans to get a deal over the line.