I recommend using yellow boxes in every quiz in which there are quite limited number of options, like here. If you guess for example countries, you know in every case at least, that it is 1/196 and you can guess all of them, if you have time. Yellow box makes that very hard, if your method is brute force.
On the other hand, if you have to know the world record holders in athletics, yellow boxes are almost same as non-yellow, because either you know them or don't know them. Maybe you have heard of Jan Zelezny, but don't know his sports, but much more likely is that you have heard of Czech Republic and guess it in every country quiz, if you can.
I recommend using yellow boxes in every quiz in which there are quite limited number of options, like here. If you guess for example countries, you know in every case at least, that it is 1/196 and you can guess all of them, if you have time. Yellow box makes that very hard, if your method is brute force.
On the other hand, if you have to know the world record holders in athletics, yellow boxes are almost same as non-yellow, because either you know them or don't know them. Maybe you have heard of Jan Zelezny, but don't know his sports, but much more likely is that you have heard of Czech Republic and guess it in every country quiz, if you can.
Would suggest something like kindergarten or neanderthal or hamster.