Hawaii, and if you're of a mood to disagree I suggest doing it quietly, and maybe just around the other haole.
Looking at https://en.wikipedia.org/wiki/Flags_of_the_U.S._states_and_t..., it’s so bad that at least 8 states feel the need to write their name in large print on their flags (Arkansas, Wisconsin, Oregon, Iowa, California, Kansas, Montana, Oklahoma; Illinois IMO is borderline large print), presumably because they fear people wouldn’t recognize it without that help.
Countless others have lots of unreadable details and small print. Wyoming, for example, would be nice if they removed that seal.
Delaware seems to have had a few flags in history that looked so similar that they wrote the date on it to make it easier to distinguish them.
For those wondering: “California Republic” comes from https://en.wikipedia.org/wiki/California_Republic. AFAIK, no such republic exists today.
Honestly I'm not sure why Arkansas's flag has its name on it; it would actually be recognizable without it. It looks like the initial proposal didn't have the name written: https://en.wikipedia.org/wiki/Flag_of_Arkansas