Not fifty jobs in a week - let's be honest, nobody's doing that - but enough applications with the same generic resume that I stopped getting responses. Just silence, or the occasional polite "we've decided to go another direction."
I've spent twenty-plus years teaching people how to use new systems, new software, new processes. Change management is literally what I did for a living. So at some point I had to laugh at myself: here I was, the guy who helps organizations adopt new ways of doing things, completely resistant to changing my own approach to a job search.
Once I actually applied what I knew - stopped sending one generic document everywhere, started tailoring each resume and cover letter to the specific job - the responses changed. Not because of a trick. Because a hiring manager can tell in about three seconds whether you actually read their posting or just changed the company name at the top.
The other thing that changed was my LinkedIn profile. Turns out a recruiter doesn't need your entire career history going back to jobs that don't exist anymore. They need what's relevant, easy to skim in thirty seconds, and clear about exactly what you bring to the table. I even took down my Open to Work banner - not because I stopped looking, but because I didn't feel like I had to take the first offer anymore.
I built Fields of Endeavor to do for other job seekers what I finally did for myself.