I am currently a COTA working in pediatrics. The work is fulfilling in that you feel like you are making a difference in the lives of children (or adults depending on your setting) and the work is fun. However, OT programs are popping up everywhere and competition for full time jobs is high. As a result, employers can get away with offering low hourly wages, fewer hours and no benefits. Your paycheck is also subject to the attendance of your patients. If you don't treat, you don't get paid! Contractors and home health professionals make better base salary. There is also talk of increasing the assistant degree to a bachelor level and the OTR to a doctorate level. That said, when you are at work, this is one of the best jobs ever. When you go home to pay your bills...not so much.
In the 18th and 19th century, hatmakers used poisionous chemicals including mercury in their work. As result, many developed pathological symptons -- an estimated 10% went insane. Hence the term "mad as a hatter" and Lewis Carroll's character, the Mad Hatter.