General terms:
* Inception: This is a formal word meaning the beginning or start of something, often used for something complex or unpleasant.
* Onset: This emphasizes the sudden or abrupt beginning of something.
* Commencement: This is a more formal word for the beginning, but can also be used in a casual way.
* Dawn: This word implies the beginning of something dark or ominous.
More specific terms:
* Precursor: This describes something that comes before and often predicts a more serious event.
* Harbinger: This word emphasizes the negative nature of what is to come, suggesting a warning.
* Catalyst: This describes an event or circumstance that triggers the unpleasant situation.
Phrases:
* The first sign of trouble: This is a more informal way to describe the beginning of something unpleasant.
* The start of a downward spiral: This emphasizes the gradual but inevitable deterioration of a situation.
The best word to use will depend on the specific context and the tone you want to convey.