system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: what is stiff suspension and why would you want it?

I’ve heard a lot of people in the car and mountain bike worlds talk about  stiff suspension. I thought the purpose of suspension was to absorb shock and make as smooth and comfortable a ride as possible. Therefore wouldn’t it be better at this if the suspension was spongy and not stiff? Why would you want a stiff suspension? Surely you could just get a fixed bike with no suspension if that’s what you want?
gpt
Imagine walking around with gigantic inflatable shoes. You aren't going to feel small bumps in the road, but walking will be a lot of work and you won't be able to be very precise about where you step or what direction you go in - that's very soft or 'plush' suspension.  
  
Now imagine walking around in a good set of running shoes. The padding between your foot and the road is still good, but it's hard enough that you can get some feedback. You can move a lot more precisely and 'feel' what's going on without feeling too much discomfort - that's stiff suspension.  
  
Now imagine walking around with wooden blocks on your feet - that's no suspension.  
  
Depending on what you want to do will decide how stiff or plush you want your suspension. Mountain Bike Racers and Racecar Drivers want very stiff, precise suspension. They want to go round corners and around obstacles fast and don't care about comfort.  
Old Mrs. Jackson in her Honda Accord doesn't need to go at 100mph to do her grocery shopping. She'd much rather a comfortable ride, so that her haemorrhoids don't flare up. She'd prefer plush suspension.