the truth is, i paid so damn much to buy into this neighborhood, it would sting to have someone pay so little to do the same.

I can empathize with this sentiment.   It stinks real bad to have others waltz in and pay less than you paid.  The resentment can fester for years.

The feeling of getting ripped-off is a very strong emotion.  American tourists overseas get pissed off if a local vendor overcharges them $2.   The amount is nothing but the resentment can last all day.   

Some people get pissed off if someone underpays his share of a meal by $1.   

When I buy my next house at 50% off (or more), I'll be careful not to rub it  in to the neighbors.