The terrorists have really mucked up our holiday plans.
If you muck up or muck something up, you do something very badly so that you fail to achieve what you wanted to. I mucked up at the 13th hole and told myself that this was getting stupid Scientists should figure out how to keep the natural world from mucking up the affairs of people. = mess up
make a mess of, destroy or ruin; "I botched the dinner and we had to eat out"; "the pianist screwed up the difficult passage in the second movement"
soil with mud, muck, or mire; "The child mucked up his shirt while playing ball in the garden"