I know it won't fit for everyone, but here it is

Anxiety: Imagine you are in a long hallway. The wall's are waterfalls. When you were young you could run under and through the waterfalls without any problem. It was fun! You loved running under these waterfalls. Then. One day, something happens, you don't know what or why, but the waterfalls are now electrified. You can no longer run under the waterfalls without being shocked. You are stuck walking down a narrow path. Sometimes, you try and do something you used to love doing, but your hand passes through the water. You collapse, ridden with shocks, fear races through your entire being. Fear without reason or object. You did something wrong. You shouldn't do that again. This lasts for a varying amount if time, minutes, hours, days or sometimes weeks, before letting up. You start walking down the hallway again. It happens over and over. You try and do something fun or new, and you become paralyzed by fear. You become like a little kid, hiding because they are afraid.

You have no choice. You MUST get up again. You walk on. You get used to walking down this path, without touching the water, without getting shocked. But one day, you get electrocuted without reason. The fear returns stronger than before. You don't know why it's back, but it is. Sometimes, the walls close in. You can no longer do actions you commonly did without being shocked.
That is Anxiety. For some, they can act perfectly normal and be fine, others can hardly smile.

Well, personally my anxiety is a little different but of course it's different for everyone and varies in severity. I do like the extended metaphor of the waterfalls though that is nice. I would describe it for myself like a constant hum in the back of your head, like static or a typical recording of muffled conversation. You learn to tune it out but sometimes the hum grows and gets annoying and stops you from being able to focus as much as you'd like. Sometimes if you do something that you find difficult, like for me catching a bus or driving, the static/hum grows and drowns out anything else inside your head and you can't think sos it's like a big thick scrabbling scribble if it were physical and you just want it to stop so you hit your head or try and block it by screaming or something else. For me that hum is always there but it spikes or drops depending on the situation.

I tell people that anxiety is like a pair of sunglasses. It determines how you see the world, makes things look threatening or scary when they look normal to someone else. It's not easy, but you can take the glasses off.

Ah okay. I figured it wouldn't fit for some people. I like y'all's explanations. That's one that just popped into my head.

That's the good thing about metaphors though, you can take it however you want that suits you best. Yours was still a good one rydler I liked it

Thank you. I will try and adapt it to fit more people.