Not who you responded to, but I have a disability (Multiple Sclerosis) that pretty much precludes me from building a successful business. Starting a successful, profitable business usually requires both working around the clock at first in order to establish it and the ability to forego health insurance/healthcare for a period of time. If I'm lucky I have 10 functioning hours a day and I need to make money to not starve so 8 is taken up with a full time job (luckily I walk 5 minutes to work so no commute). I also still need to shower, eat, and exercise to keep my physical condition from deteriorating. On bad days I'm sneaking in naps at work because I have less than 8 hours of good functioning. Weekends are usually spent recovering (sleep/migraine).

Basically anything that eats up your time. Disability is just an example problem that nobody can blame on us.

Edit: It doesn't need to be severe, which is why I mention it. I'm actually better off than 95% of MS patients.