In the Philippine legal system, Unjust Vexation is often described as the "catch-all" provision for annoying or harassing behavior that does not fit neatly into other specific crimes like physical injuries or threats. It is governed by Article 287 of the Revised Penal Code (RPC), as amended by Republic Act No. 10951.

The essence of the crime is any human conduct which, although not causing physical harm, unjustly annoys or irritates an innocent person to the point of causing mental distress, even if that irritation is only temporary.

The Elements of the Crime

To successfully prosecute a case for unjust vexation, the following elements must be established:

The Offender performed a human act.
The Act caused annoyance, irritation, torment, or distress to the victim.
The Act was committed with "malice" or the intent to cause such vexation.
The Act does not constitute another, more serious crime (e.g., Grave Threats or Slander).

Note: The test is whether the act would annoy a person of "ordinary sensibilities." It is not based on the overly sensitive reaction of a specific individual, but rather on what a reasonable person would find vexatious.

Step-by-Step Process for Filing a Complaint

1. The Barangay Conciliation (Mandatory Step)

Since Unjust Vexation is a light offense, it falls under the jurisdiction of the Katarungang Pambarangay (Barangay Justice System).

The Rule: You cannot go directly to court if both parties reside in the same city or municipality.
The Process: File a complaint with the Lupong Tagapamayapa of the Barangay where the incident occurred.
The Outcome: If no settlement is reached, the Barangay Captain will issue a Certificate to File Action, which is a prerequisite for filing the case in court.

2. Filing the Complaint-Affidavit

Once you have the Certificate to File Action, you must prepare a Complaint-Affidavit. This document should detail:

The specific dates, times, and locations of the acts.
A clear description of how the acts caused annoyance or distress.
Evidence such as CCTV footage, screenshots of messages, or witness statements.

This affidavit must be sworn before a Prosecutor (at the City or Provincial Prosecutor's Office) or a Notary Public.

3. Preliminary Investigation / Inquest

The Prosecutor will evaluate your complaint.

Subpoena: The respondent (the person you are complaining about) will be served a subpoena to submit a Counter-Affidavit.
Resolution: The Prosecutor will determine if there is Probable Cause. If yes, an "Information" (the formal criminal charge) will be filed in the Metropolitan or Municipal Trial Court.

4. Trial

Unjust Vexation is subject to the Revised Rules on Summary Procedure. This means the process is intended to be faster than regular trials:

No full-blown preliminary investigation is required in some jurisdictions.
The court may decide the case based on position papers and affidavits rather than lengthy oral testimonies.

Penalties

Under Republic Act No. 10951, the penalty for Unjust Vexation is:

Arresto Menor (1 to 30 days of imprisonment); or
A fine ranging from PHP 1,000.00 to PHP 40,000.00; or
Both, at the discretion of the court.

Important Considerations

Prescription Period: You must file the complaint within two (2) months from the time the incident occurred or was discovered. If you wait longer, the crime "prescribes," meaning you lose the right to sue.
The "Broad" Nature: Because the law is broad, Philippine courts have applied it to various scenarios, such as cutting off a neighbor's water supply, persistent unwanted phone calls, or blocking a driveway without legal right.
Civil Damages: Aside from criminal penalties, you can also pray for Moral Damages and Attorney's Fees as part of the civil aspect of the criminal case.

Comparison Table: Unjust Vexation vs. Related Offenses

Crime	Key Characteristic	Penalty Severity
Unjust Vexation	General annoyance/irritation	Light
Grave Threats	Threatening a wrong/harm	Serious
Oral Defamation	Harming reputation via speech	Less Serious to Serious
Physical Injuries	Actual bodily harm	Varies