• Android programming. Tried it once, wasted many days trying to make sure the app works on all phone models ranging from $10 to $1000. There were some hardware-related parts that are poorly standardized and abused by the manufacturers a lot. And yeah, the $10-$1000 range coverage is a bit too much for such a poorly designed platform.
• Inkscape: if you are a perfectionist who regularly checks the SVG sources generated by Inkscape, then... you may develop insomnia. The bloody thing will stuff the file with garbage by some 90%, and will get all your coordinates un-rouned to some unreasonably distorted numbers. No, it's not the "floating point thing", it's worse. A few times I ened up writing up the SVG file by hand from scratch, while checking it in the browser. Inkscape is outrageously bad.