New Hampshire rules and tradition quite clearly states that neither applause or booing is ever in order. It is up to the Speaker to enforce this policy fairly so that the House does not get out of control.
However, in his final day (hopefully) of wielding the gavel, Speaker Bill O'Brien appeared to go out of his way in soliciting applause when House Republicans overrode some gubernatorial vetoes. O'Brien announced the passage of the photo ID for voting bill in such a manner that just begged applause.
Sure enough, Republicans begin to hoot and holler, and the Speaker allowed it.
It happened again moments later on another bill, more loud applause on an override.
However, apparently what's sauce for the goose is not sauce for the gander. Later in the day, when Republicans were on the losing end of a veto override attempt, a few Democrats cheered. Not only did the Speaker point out how inappropriate this was, he actually named names (he admonished Durham Rep Tim Horrigan to control himself).
A fish rots from the head down, and this fish once again, hopefully for the last time, showed how rotten it is.