Touchy subject. FO's job involves being both a pilot and a psycologist. It's a tough job.
As an FO I remember being scared by my Captain's decisions once, and it only turned out to be an approach with a "bank angle" and "terrain" GPWS aurals and an interesting landing. All I did was keep an eye on the terrain, airspeed, and configured the AC as he was too focused on his bomb run to ask for checklists.
I did take the controls once when my Captain was looking for the runway leveled at the MDA on a VOR approach to minimums with decreasing airspeed (below Vref) and a very long decelerating trend vector on the PFD. He appologized, took the controls again and there were no hard feelings. Another Captain could've been more emotional about that.
As a Captain I'm sure I have scared new FOs with visual approaches with 3 mile finals and also approaches and takeoffs in bad weather, but most things are new to them at that point.
I really doubt retracting the gear is a safe thing to avoid crazy landings. Just sitting there isn't good either. I think I would try the old "Captain I don't think we are going to make it, wouldn't it be better to go around?", or maybe just recruit better Captains.
rcl