a bridge too far

cliché An act or plan whose ambition overreaches its capability, resulting in or potentially leading to difficulty or failure. Taken from the 1974 book A Bridge Too Far by Cornelius Ryan, which details the Allies' disastrous attempts to capture German-controlled bridges in the Netherlands during World War II. The multi-million-dollar purchase of the small startup proved a bridge too far for the social media company, as the added revenue couldn't make up for the cost in the end. Look, I'm happy to help you guys out, but I'm not willing be the primary investor in your invention—that's just a bridge too far. Apparently, signing an A-list player is just a bridge too far for this team! They'd rather wallow in their mediocrity, I guess.