Do you ever wonder if some end-user is sitting at their desk right now, eye twitching spasmodically while a screen you helped write takes 30 seconds to load, cursing your name and the names of your children for all eternity? If you're on a team, at least you can all share the blame. If it's an older company, you've got legions of bygone devs to toss under the bus too. Bonus!
When I left my first gig, I took solace knowing I was giving the team some breathing room for a few months. "That laggy finance screen? Those slow reports? The login timeout issue? Yeah, those were all part of Grant's last project.. the, uh, financial reporting authentication project."
In all seriousness though, devs don't dev on the same caliber of machine the consumers of our code will be using, and for good reason. Daily, I'm running several large pieces of software that a customer will neither have nor need. They may be running on a top-of-the-line machine, but it's doubtful.
There's this post from way back proposing a programmer bill of rights (oh boy), one of which was apparently fast dev machines. And there were like a dozen comments under it with some version of, "No no nonono, we don't need faster computers. We'll just make software even more bloated and the end users will find it even more frustrating to use!"
While reducing dev laptops to whatever that worst case might be is a ridiculous idea, I wonder, in the age of virtual machines, if it wouldn't be reasonable to setup a vm with severely limited resources - worst case scenario - and occasionally run the software in it as a reality check. I may have to try that out sometime...