It’s always hard to say you’re sorry, but anytime 50 residents turn out to a routine meeting of any community board, you know something has upset a large segment of the public and an apology may be in order. And so it was on Tuesday when a crowd addressed the Middlebury selectboard on what many perceived as overzealous work to shore-up town bridges and a retaining wall in the river that, as a consequence, has done what some say is irreparable harm.