I feel like I was layered upside down... The layers I wanted to take off are buried.
personally not a fan of tight mid layers. I feel constricted and feel colder often. Or if it is warm, too easy to overheat, ventilate.
The between layers are tough. I like zippered wind stopper, fleece, softshell layers that offer variability.
For XC/BC skiing: baselayer, (definitely short sleeve to show off fore arms on a sunny spring day...) zippered fleece, shell. If it is warm, just unzip. If it is ludicrously hot, it won't be too uncomfortable to delayer down to the baselayer. For a decent or if it is cold, I can put a puffy over the fleece without getting too cold.
For climbing, I do similar, though I might want more layers available. Typically more alpine start, night time, early morning activity.
Pretty dependent on temps and conditions. 35 and Pacific Northwest sleeting, 20 and a rocky mountain blizzard, 10 and nucleating intermountain mist... Climb chilly. If you are comfortable when you start aerobic activity, you will sweat. And that's bad, mmm k. I have a layer available to warm up. Typically a puffy or a loose fleece in the top of my pack.