Aries- They don't.
Taurus- Mom said dinner was ready but she lied.
Gemini- Because all the irritating little things that happen rarely happened all on one day.
Cancer- Because they feel like it.
Leo- Because school is bound to make even them cry one day.
Virgo- Everyone is so stupid that it makes them sad.
Libra- The nutella jar was empty.
Scorpio- Going through an emo phase.
Sagittarius- Allergies.
Capricorn- Cutting onions.
Aquarius- ...who knows? It's a mystery.
Pisces- Their favorite character died.