In the subject line of "Bill added by ..." email, include the amount you owe.
It apparently gives my roommate a mini heart attack every time she sees "Bill ($$$$) added by Person".
Please consider altering the subject line to something like "Bill ($$$$) added by Person (you owe $$$)". Hell, maybe just leave the amounts out of the subject altogether, and leave all the details for the body of the message.
This does seem like a good change. I suspect we’ll wind up leaving the amounts out of the subject line all together