Internal monitoring dashboard that was made in PHP4 that was really slow (even for PHP4 standards) due to doing a lot of unnecessary things.
Fully uncommented, fully undocumented elsewhere, massive fustercluck of code.
Had to change at least 300 methods in order to make is somewhat run decent (sadly, I wasn't allowed to just rewrite from scratch, which would have been a lot faster)...

Just your regular SNAFU.

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