I hate when plans change!!!!

Ugh I cannot stand it when people change plans last minute, especially 2 hours before. It has to be one of my biggest pet peeve, considering it's been planned for almost 2 weeks!!! Bill and I are supposed to go to six flags today with 2 of his friends and we were gonna go around 1 since it's only open til 10, and when I went to text him at 11:15, he had texted me saying that we couldn't go til around 5 since his one friend doesn't get off work til 4:30. His friend waited until today to tell him that! My day was totally thrown off because of that. I really hate when people cancel or change their minds/plans last minute!!!!