Whenever you get water or sugar on your hands, it probably won't stick. On the contrary, that all changes when you add some moisture and heat. The stickiness of some of these mixtures can be explained at the molecular level.
There are a variety of sweet fluids that are sticky to the touch, including honey, molasses, and syrup, among others. These all have two things in common: water and sugar. The two components have differently-sized molecules that flow in distinctive ways, and the molecules have a certain amount of exposed charges that stick to a select number of other molecules.
Mixing the two kinds of molecules in the same container presents each of their best qualities. Sugar's larger and stickier molecules flow more freely through the smaller water molecules, but they still try to lock together by their charges.
When you add the right balance of stick sugar molecules to free-flowing water, this slows the flow rate down significantly. In a nutshell, this is what causes the thick, gooey, and sticky properties of some of the viscous byproducts mentioned earlier.