1.) The Pay
It's all about the money, right? I mean, who would want to put up with the barrage of family members asking for free repairs, sniffing brake parts cleaner all day, the greasy hot environment, included responsibility of work quality, the fear of loosing the use of your back, and the constant education that's required to get you no where? No one would put up with this stuff if the pay wasn't up to par.
That's where you are wrong. The pay in this field CAN be very good, but there is potential for good pay in any field to be good. Even Walmart has some high paying positions, but most people who work there are stuck with something close to minimum wage. These high paying jobs are far and few between. A position on a NASCAR team would be fun and likely pay very well, but again these positions are not very common. That's what these private schools try to show you. These high paying jobs that don't come around often.
Lets just talk about the median salary for an automotive technician. For a senior technician, the median is a modest 52K a year. Lets also remember that there are several types of pay for the technician. Salary which is rare for this job, Flat-Rate which is common, and Hourly which is somewhat common. A entry level position only earns a measly median 35K a year. All those occupational risks and schooling to make less than the average pay for a Garbage Collector. I'm not kidding. I am not bashing on garbage collectors, they are generally in good shape to do such a physical job.
Even look at the fast food industry. If they get their wage hike they are asking for, they will be making 32K a year but you having a associate degree with student loan debt and thousands of dollars in tools only make an few extra dollars per hour. Before you know it, years have flown by. Congrats, now your just as stuck in this career as the rest of us. Might is well stay with the ship now.
Conclusion: I'm not trying to scare you away from this career but you need to be prepared for what lies ahead. I am happy with working on cars. I am semi-happy with my pay for all these years of experience, so far. If everything I have wrote about today has not scared you off, then perhaps this is a great career choice for you. Maybe you will be lucky and be happy too.