I bought my first road bike from a friend and it had one sided SPDs on it. The non-SPD side is lethally slippery metal, so I got over clipping in really fast, since the alternative was flying off the pedals (or buying new pedals, but I'm cheap . Those pedals are still on my other road bike. I have had a couple uncomfortable moments in deep sand (leftover from flooding), snow, ice, and on a particularly big hill with a big load of groceries on the commuter but always gotten out.

I WAS scared to ride clipless on the fixie, but that has nicer platform/SPD combo pedals so I compromised and rode clipped in on one side for awhile until I was more comfortable and now it's easy and I vastly prefer being clipped in on that bike now.