Counteroffers
At one point in the past, I accepted a counter offer after planning to leave, and, well, it worked out ok, all in all. However, this guy is very much against it, and his logic is quite sound. For me, the counter-offer was structured so that I moved into a brand-new, tiny organization focused on new technology, so the drawbacks he cites weren’t really in effect. Absent that kind of opportunity, I would definitely agree that you should not accept a counteroffer.
Certainly as a boss, the only time I would make a counteroffer is if I needed someone for a short-term emergency. Once that was over, I’d certainly cut them loose.