When you have to debug a system made by a freelance agency that only had to get it working and not maintain and support it, leaves you with that feeling;
Their stack: https://m.xkcd.com/1636/
Their tool chain: https://m.xkcd.com/1579/
The actual resulting code: https://m.xkcd.com/1185/

And nobody can see why performance is suffering — it's all so simple and beautiful...