Literally nothing on Linux has compared to MS Paint. It's nuts.
This has to be the number one thing I hate about Linux: everything feels like an inferior, makeshift mockup of Windows software. Everything has that "made by one person in their garage, held together by spiderwebs and magic" feel to it.

KolourPaint is almost there, but not quite. Also, it's KDE so on GNOME all the button icons will be missing.

GNU Paint. Absolute crap, sorry mate.

Pinta. Pretty good but the GUI still sucks and some handy shit is missing like resizing canvas straight from pulling on the corners. With some extra work this could rival MS Paint

GIMP. Way too overkill for everyday use. Mostly for photographers. Sure, it's capable, but the user experience is not what most people are looking for.

Krita. Still too overkill if you just wanna put text on cat pictures, mostly for furry artists.