One of the things that irks me the most about cricket, is the loss of play and the inability to get all the scheduled overs in five days. It could be due to rain, bad light, or even (and this is the worst) a side taking unusually long to get ready between balls just to delay.
If we had a sixth day scheduled for all the tests, and only the overs that were left over from the previous days would be bowled...would you all like it? I think that anything that allows 450 overs to be bowled in a test match is a good thing for cricket. If all the scheduled overs were bowled, then there would be no play on the sixth day of the match.