Someone's already mentioned the England v New Zealand game at the Olympic/London Stadium. God, that was ... the last time I took anyone new to a game. And all wrapped around with the worst matchday 'entertainment' possible. In my entirely humble opinion, the fact that England can't even get any fixtures confirmed can probably be traced to the attitude and delivery of that day.
Otherwise, London Broncos 12-10 Hull Sharks lingers as being just awful but there was a game against Huddersfield a few years later where I remember an ironic round of applause because two consecutive passes were held. That match could easily have had more knock ons than spectators.