My coworker consistently complains about their job. Why do people stay in jobs they hate?

Risk aversion and inertia. People write whole books about this topic.

I would think a person stayed in a job they hated because they have no other options to get another.

For the money...its just that simple.

they are scared of change and they need to put food on the table

Money, security.

Its become easier to leave jobs they hate. The past reason was lack of jobs available or under qualified.

They are comfortable where they are. They probably have commitments that makes them more worried to leave without another job lined up already, for example, they have family or big dent to pay off.

I have never had a co worker complain about their job. People stay because the can learn and make a difference

Fear of change, there are other job lerks they like but do not talk about it.

Paycheck and Healthcare is better than anything else out there.

Most jobs suck. The lucky 1% work at a good job. It’s so easy to say “find a new job”. Hard to actually get one. Flaky recruiters, not knowing the right people, etc. I hate my job but it’s all I can get right now.

Laziness, usually, but sometimes people feel they have no other options.

Because they do not believe in their self. They are in a rut that they put their self in and believe they can't get out.

They are often stuck and don’t know how to fix it. So they stay put. Or they deep down are anxious about their own power and ability to get what they want

I've never stayed in a job I hate.

The pay and insurance; stability.

Because it is all they know, they great change

They might not want to start allll over again at a new job, the process, meeting new people, learning new things and trying to do it right. They may not think theyll be able to get another job at the moment, etc

Financial reasons and laziness

Sometimes people are internally unhappy with themselves and will bring that along with them to any job.

They are afraid of change