Corrected entry: Ronald smashes the baseball bat on the lunch table, shattering the bat. Seconds later, he gives the bat back to the guy and the bat is in perfect condition.
Corrected entry: When Ronald shows up mowing Cindy's lawn at 6am, it is fully bright outside. Not possible. It's January (since just after the New Year's Eve scene) and in Arizona during January, the sky is still fully dark at 6am (about 6:15 to 6:30 it would start getting a bit of daylight).
Correction: I believe several weeks, maybe even a couple of months have passed since New Year's Eve. After Cindy exposes their secret to everyone there are various scenes of Ronald trying to make amends with Kenneth and attempting to get Cindy to talk to him again. When Ronald stops Quint from beating up Kenneth and makes his final speech the jocks are all dressed in baseball uniforms indicating that it is spring. I believe the scene where Ronald woke Cindy up with his lawnmower actually occurred in March or maybe even April as opposed to January. I think we are supposed to assume a lot of time has passed from the time Cindy exposed Ronnie to the point where he finally got her attention with the lawnmower.
Correction: He doesn't shatter the bat (which would be impossible, anyway), he hits a tray of food, causing it to splatter. After this you can see the bat in his hand and it's undamaged.