In the last month I have quit 2 jobs after the 1st day of work.

In October I got a job at a warehouse because I needed money and I use to do that kind of physical labor work when I was in my early 20's. The job wasn't difficult or stressful it was loading containers. It's hard work but I'm pretty fit for a 40 year old. The next day I didn't go in to work because the job felt dead end and needed something that will stimulate my mind.
A few weeks later I find another job through an agency. The job was in manufacturing in which I have lots of experience in. The job started at 5am and I wasn't happy about getting up at 3:30am to get ready for work. The job was boring it was basically helping a machine operator load parts on to the machine. The next day I slept past 5am and didn't go in to work. I basically called the agency said it wasn't for me.
The thing that bothers me is that quitting is started to be a habit for me. The longest job I held was for 7 years and I loved that job, unfortunately it closed down in late 2007 or else I would be still working there. After that job I worked for various temp agencies working on job assignments that lasted anywhere from 3 weeks to 6 months. Till I was fired from one and collected unemployment benefits for 2 years. Now I'm back looking for work but can't find anything I like to do, something that will challenge me.