As Goat mentioned, the only imperfect care is when you allow a care miss
. Generally, which food you feed to satisfy hunger doesn't matter, and whether you feed snacks or play games to fill the friendship bar makes no difference. (There's no penalty for reaching 99g weight.)
It seems there are some special methods to getting certain characters though, so even if you're on track to get a certain character based on care miss
requirements, you may end up with someone else.
Hirotchi = connect any male teen to 6 or more different friends.
Maisutatchi = connect any male teen to the same friend 30 times or more.
Mametchi = on 3 or more occasions, activate the toilet icon while Hanikamitchi (male teen) is doing the pee-pee wiggle dance, before he messes on the floor.
Kuishinbotchi = feed 20 or more snacks to Bokuhoshitchi (male teen).
Sunopotchi = have Happabouyatchi (male teen) get a perfect score on a minigame, 20 times or more.
Madonnatchi = connect any female teen to 6 or more different friends.
Giragiratchi = connect any female teen to the same friend 30 times or more.
Lavulitchi = on 3 or more occasions, activate the toilet icon while Painaputchi (female teen) is doing the pee-pee wiggle dance, before she messes on the floor.
Perotchi = feed 20 or more snacks to Sabosabotchi (female teen).
Ponpontchi = have Hineonetchi (female teen) get a perfect score on a minigame, 20 times or more.
Note: Information about the above growth paths are from these sites:http://e-mani.net/tamagotchi/http://blogs.yahoo.co.jp/sapphire_piano/23046201.html