Ask HN: Why would you accept a horizontal move in your career?

What is the main reason why you would accept an offer and move horizontally from XYZ to ABC, without being promoted to the next level.

1- Salary?

2- Tired of your current job/employer?

3- Location?

4- Simply looking for a new place to work?

5- Other, specify.

Horizontal move = Sr. Software Engineer at XYZ => Sr. Software Engineer at ABC

Vertical move = Lead Software Engineer at XYZ => Engineering Manager at ABC