ELI5 Escalators - what is the shoe shine thingy there for?

Why does it feel so strange to step onto a stationary escalator? What do the brush type things on the side of escalators do? Why are escalator steps jagged with the brushlike shape at the top and bottom? Why do escalator handrails often run at slightly different speeds than the steps? Why does it feel so strange to step onto a stationary escalator?

... we explain like I'm five

Thank you to the r/explainlikeimfive community and in particular the following users whose questions and comments formed the basis of this discussion: ferdinand00, v0kun, banauuuuh, teddyjules, rashikun, south5, ac7ss, voltenic and aptom203

To the ELI5 community that has supported us so far, thanks for all your feedback and comments. Join us on Twitter:

https://www.twitter.com/eli5ThePodcast/

or send us an e-mail:

ELI5ThePodcast@gmail.com