howdid that happen i was hapliy playing on my tama and suddenly i got a messege i went on it and i had mess for my messege and my tama had only one happy heart
Well, that is normal. Sometimes, a mail may come in for your tamagotchi and you open it, and it is a mess, like you said, There are also times when there is a snake. Also, you may get a heart in the mail too in which you will get all of your happy hearts full, which is really good and makes your tamagotchi happy. It is normal so there is really no way to prevent it and there is no way of knowing if it is a snake, a mess, or a heart.
If you feed it snacks, then yes. One snack gives the tama one happy heart. You may risk getting a cavity if your tama is still a baby, toddler or teenager though. Plus, it will gain weight. You can play a game and get a perfect score in it to restore all 4 happy hearts in one go.
You can also feed its favorite food as well to gainback its happy hearts.