Honestly, this is a topic that makes me physically ill.

You are ignored just a little bit more than enough to think you are invisible. When someone does catch your attention, it was accidental and they quickly look away to make it seem like they were just glancing around. When they think you're not looking, you get scowls and disgusted looks. When you are in close proximity, people make VERY clear signs that you are not welcome. This could be as simple and unassuming as someone turning their back to you in forced close situations - such as waiting at a deli counter. Or it could be as extreme as someone saying something like, "Sir, can I help you? I THINK YOU NEED TO LEAVE. NOOW!" While you're literally just walking in the middle of the sidewalk, looking at the ground and nothing in particular, lost in your own thoughts.

These things seem innocuous, but it has gotten to the point where I fear that someone will call the police and I will be arrested based on people's looks alone. Its devolved enough over that past few years to the point where I vehemently avoid leaving my home and have been diagnosed with social phobia and general anxiety disorder.