I had opportunity to watch a couple self-propelled sprayers in operation on several farms today purely as a spectator. The thing that struck me was how violent and aggressive they looked as they lurched across the fields.
On sidehills, I cringed with how often the boom tips dragged or threatened to drag the ground. Crossing waterways and terraces, I saw one of the machines literally lift one of the front wheels off the ground. One operator decided to blast through a short wet spot and flung chunks of mud off the front tires onto the roof of the cab.
As a mechanic, I was a little frustrated at the abuse the drivers were inflicting on their machines, until I started watching the operator in each cab. For the most part, the operators were floating comfortably along on their air-ride or hydraulic-suspension seats. I realized that they were watching out the front nearly full-time, trying to stay on top of things at 15 miles an hour, and trusting the machine's suspension system and automatic boom height control to deal with rough spots in the field.
The longer I watched, the more certain I became that if those guys "locked" their seat suspension, they'd drive a lot more carefully, especially in rough spots. Sophisticated seat suspensions make operating farm equipment a lot more comfortable, but a smooth ride can come at the cost of repairs to components on the machine that aren't aren't as well cushioned as the operator's fanny.