I didn't see where the OP said they went into a "Disney park thinking maybe someone will be nice to me today"..
I think some complaints are based on legitimate shortcomings and problems in the parks, with the CMs, with things not working propertly, etc. On the other hand, there are certainly some naturally grumpy people out there who are just going to be peeved at whatever, and could do with an attitude adjustment.
What bugs me is when people assume that the latter is going on, when maybe it's the former. Is is possible that this OP has a great attitude, but is actually having some objectively bad experiences?