Raises, vacations (when I was at companies that gave them based on tenure), promotion considerations, you name it.
I recovered a bit since I was working on side projects during sabbatical and could talk for them in interviews, so switching companies helped a tad (though finding someone who would hire someone with a big hole on their resume wasn't easy).
There's also just stuff that you only learn on the job and can improve on indefinitely, like managing people, projects, etc that obviously was behind by the amount of time I was off work and meant I wasn't up to snuff for some opportunities.
I recovered a bit since I was working on side projects during sabbatical and could talk for them in interviews, so switching companies helped a tad (though finding someone who would hire someone with a big hole on their resume wasn't easy).
There's also just stuff that you only learn on the job and can improve on indefinitely, like managing people, projects, etc that obviously was behind by the amount of time I was off work and meant I wasn't up to snuff for some opportunities.