1. This one is complete hindsight, but still it makes me cringe thinking about it. Last year I drafted Gronk in the second to last round of my 12 man league. After the draft I dropped another guy and picked up Hernandez. This was before Gronk showed any signs of being, well, Gronk. Dropped Gronk after Week 1 when Hernandez put up a good stat line. I figured Hernandez was the better option as he is more of a hybrid WR/TE and they split him out sometimes as a WR instead of blocking which Gronk does more of. Then Gronk went Gronk on everyone, and you know the rest.
2. This year, I'm looking to pick up a bye-week filler WR in one of my public leagues aside from my 2 money leagues. Girlfriend called me on the phone and I got distracted and I ended up dropping Andre Brown whom is my handcuff to Bradshaw in one of my money leagues thinking I am in my public 10 team league where RBs are dropped every week (and I don't have Bradshaw in the public league). I realized after what I had done, and since I was the one who dropped him I couldn't put a waiver claim in when he became a FA. Someone snatched him up.