It really depends on the age of the girl for me. I have a very broad range of lolis that I am attracted to personally, ranging from toddlers to just before puberty starts.
For the younger tot girls, many times wearing diapers for them will just feel like the most natural thing in the world. They'll happily romp around with their diapers exposed without a care in the world.
For slightly older lolis who by normal standards shouldn't be in diapers, I've had diverse fantasies. I love to fantasize about little girls who think they are bigger than they are, and try as they may to be big girls, they always fail to make it to the toilet in time, and thus always end up diapered again. That is always very cute, especially if they are a bit stubborn but don't take their failures all that seriously.
Immature little girls are also very precious. She doesn't want to grow up, and doesn't feel the pressure to change along with the other girls her age by getting rid of her toys, not watching baby shows and of course wearing big girl panties. She'd be very stubborn and would have "accidents" just so she could stay diapered. I imagine this little girl would grow into a big ABDL as she got older.
More unrealistically, it's sometimes fun to imagine naughty lolis who flash their diapers at their babysitters and put their diapered butts on his face and boss the babysitter around totally not a self-insert fantasy