The Frenchman, who took over in September, saw his team move out of the Barclays Premier League relegation zone with a 1-0 win over Manchester City at the weekend.
A goal from £18million signing Darren Bent on his debut on Saturday enabled Villa to gain revenge for the 4-0 humiliation at Eastlands on December 28.
And, with one defeat in five games ahead of the meeting with Wigan, Houllier admits his camp is a lot happier than the last time they faced City.
He explained: "You can't prepare for a game if someone is pulling a face - it drains the energy. And there was a time when the players playing were moaning and whining.
"We probably have the best job in the world so when you see unhappy people not doing basic things, like being focused and ready, you get angry."
Source: PA
Source: PA