Spiders only put glue droplets on some of their strands of silk, and they tend to avoid these as they move around their web. Spiders also only touch the web with the tips of their feet (‘tarsi’), which have a non-stick coating.
In addition, a special claw on the end of each foot grips the web and pulls it against springy hairs. When the claw is released, the springy hairs push the web strand away, stopping it from sticking.
Luis trained as a zoologist, but now works as a science and technology educator. In his spare time he builds 3D-printed robots, in the hope that he will be spared when the revolution inevitably comes.