Well for physics, the three-body problem, you see it in the first year, the Roche limit - in second. (Specifically two spheres coming close does NOT result in infinities, pointlike objects do - but then you also learn around the same time that atoms aren't pointlike objects and at nanometer-short ranges you have to start to deal with other forces than gravitation too...)
(I have my own beef with the "sweeping under the rug" which happens with (electromagnetic) pseudovectors, but I do realize that requires a LOT of effort to fix.)
(I have my own beef with the "sweeping under the rug" which happens with (electromagnetic) pseudovectors, but I do realize that requires a LOT of effort to fix.)