While I realize we're not talking about religion or spirituality in any sense, you've effectively illustrated the difference between my spiritual path and conventional religion. If you give money to the church, it doesn't matter that your intension is only to get that letter so you can increase the deductions that you claim on your taxes. You gave money to the church so you got a gold star in God's Big Book of Good Deeds (Catholic Edition).
On the other hand, money or acts don't mean shit in paganism without the right intension. If you give money just to look good to other people, if you do a good deed with shitty ulterior motives, it's ethically/karmically bad.
There's no "getting back" at the neighbors, why rent them space in your head to begin with? Smile and wish them well and move on. If you don't sleep in their bed why do you even care what they do or think?