Throwing my two cents in.
I have been extremely meticulous in weighing food and tracking measurements, supplements and weights, along with calorie expenditure. I have over a years worth of data in my excel spreadsheet which I update multiple times per day. Everyone is different, but I suspect this will be accurate to more people than they realize.
1) People are much, much fatter than they think. Even well trained individuals. I was a well trained individual and I under-estimated the amount of fat I was carrying. I see people say "I think my ideal weight would be 180 @ 10%" this person will be like 5"'6"... Sorry to say, but that isn't going to happen. If you think you need to lose 10 to look great, try '30' and the main reason for that is because people don't understand the role of glycogen and it's impact on weight. The first 10 pounds on any diet should be discarded and counted as mere 'water loss' sure, some of it will be fat loss for sure, but people will do much better to count that 10 as mere 'water' because 90% of it is water and waste...
2) People don't really understand glycogen depletion, repletion and super compensation. My weight without deliberate manipulation (As in, trying to drop water weight via sauna, diuretics, etc..) has gone from a 170.0 (glycogen depleted) low to a 186 (Glycogen super compensation) within 36 hours of a carb load and no actual fat was gained.
3) Creatine can and will increase water weight, but this is good water weight. It typically draws water into the muscles and not into the subcutaneous. But the water is just a by-product, the real gain is the extra power. After tested on my self, the difference between no creatine and fully loaded was over 5 pounds in my case of retained water. It gives a more fuller look. Drop creatine on a cut will cause you to drop even further weight (in addition to that of glycogen loss) which some people will assume is 'fat' - again, some of it might be, but most of it is just the loss in water volume.
To give me example, if I drop creatine and deplete glycogen substantially, I will drop to 165. Carb loading will bring me up to 180 (super compensation) and then added creatine over the course of the next month will edge me up towards 185 @ maintenance. If I load, even faster (can gain the weight in as little as 7 days if I creatine load)
There is a saying... "You can't manage what you don't measure." and it has taken me over 8 years to finally put the dots together. For an article, I find interesting, check out:
Glycogen storage: illusions of easy weight loss, excessive weight regain, and distortions in estimates of body composition.
http://ajcn.nutrition.org/content/56/1/292S.abstract