Between the end of last season and now, what's been your biggest regret, move-wise?

For me it was blowing some offseason FAAB on undrafted rookies in our league that were starting to get some camp hype and/or making the 53-man rosters. Because then after week one I know I would've spent pretty much all my FAAB on Jordan Mason (14-team league with 27-man rosters so free agency is a wasteland) but I couldn't get him since I couldn't get the highest bid. Even if I sold lower on him a few weeks ago, I'm sure I could've turned him into a 2nd which would've been useful as a rebuilder.