Okay, I wanted to make a glitch list and how to solve them. Some I don't know how to solve, so you can contribute if I know! Some aren't glitches, some are just random questions.
Q: My Tamagotchi is 3 years old and still a baby?!
A: If you leave your Tamagotchi on the "name" screen for a few days, the age will be how many days you left it for. It will grow regularly (thanks chocosilver!).
Q: How do you un-debug your Tamagotchi?
A: Open it up and erase the pencil marks in the Tamagotchi.
Q: Why is there an X on my screen?
A: The battery is low. Buy a new one or take the old one out (people say you need to put it in the fridge but you actually don't really have to). When the old one's out for a time you can put it back in and your Tamagotchi SHOULD work perfectly.
Q: What's the growth process?
A: Baby for an hour. Child for a day (24hr unpaused time), Teen for 3-4 days (72hr unpaused time). Finally, adult until it marries and has a baby or until it dies of old age.
Q: Why is there a ball in my snack section?
A: The ball sometimes appears when your Tamagotchi v3 dies and you hold A+C. You can feed the Tamagotchi the ball and usually nothing bad will happen but I have heard somewhere that it can FREEZE up your Tamagotchi
Q: I dropped my Tamagotchi in water and now it's going crazy!
A: ???
Q: My Tamagotchi keeps resetting itself!
A: ???
Q: My Tama's pixels got all weird and they had messed up for a few seconds!
A: It could be a reaction to a sort of heat. Move away from any heat source. If you aren't near any heat source, reset and download.
Q: I have a teenager that's 0 years old?!
A: Resetting and downloading can stuff up the ageing process. Inside is a little "clock" that, after 24 hours tells the Tamagotchi to age once more, I think. When you reset and download, you have reset the clock too. Your Tamagotchi will stay the same age but will not age too quickly now. I've had a 0 year old Ichigotchi.