If they are on sec 8 I think you may be able to reach out to their case rep and let them know they are being unreasonable

This is really an unreasonable argument, in my view.

I have one now where the terms of the proposed agreement (seller's attorney drafted it) were considered unreasonable to the neighbors.

Sounds like their ask is unreasonably large and also not supported by anything.

For example, landlords may not locate families with children in any single portion of a complex, place an unreasonable restriction on the total number of persons who may reside in a dwelling, or limit their access to recreational services provided to other tenants.

That doesn't sound unreasonable for plans & permits, but what does the scope of the interior design work include?   

This felt very unreasonable at the moment withe able to remedy a solution. 

Appraisals aren't foolproof, but maybe it can help ground their unreasonable expectations.

Every property we looked at had unreasonable ARVs and comps.

I did my calculation, if I keep it long term - I mean really long term, suppose the property goes up to 840k in 13 years, not unreasonable, by that time my 15 tear mortgage is paid off..so I will have 850 minus 500k gain * 15% long term tax = $75k, so I after tax will have 775k, compare to sell it now and net 380 or 390k.