(m01229)We’ve heard a good share of “pay it forward” stories at coffee shops and elsewhere, where customers ask to pay for the next person’s order, sometimes leading to a chain of people willing to brighten up a strangers day. But one Pennsylvania Dunkin’ Donuts has probably seen more of these pay it forward acts than others: the manager says it happens every Friday, no matter what, like clockwork. Sometimes only two customers participate, sometimes 12 — and sometimes, the chain of giving would last even longer, if only there were enough customers in the drive-thru line that day, the Dunkin’ Donuts manager tells the York Dispatch. He started noticing the Friday pattern after he began as a manager at the Dunkin’ Donuts.