You can create friction to grip things because of these small ridges on your hands which are better known as fingerprints. T
Geckos have an amazing ability to grab onto almost any surface. The reason is because they have even more ridges than we do. It's like their ridges have ridges and then those ridges have even more ridges except that when you start to look into the object's on a microscopic scale, you notice that they don't look like ridges anymore. Now they look like small hairs and these are so small that they actually interact with the surface they are on at the molecular level. Because there are so many small hairs, these interactions end up adding up to a very strong interaction between the feet of the gecko and the surface s/he is on.
The following is a link to a 5 minute video that discusses the physics behind the gecko's sticky feet.
- Van der Waal's Force
- firemen scaling walls