It's completely normal for babies to have cold hands and feet, even when they're warm and comfortable. This happens because babies' circulatory systems are still developing - blood goes to vital organs (brain, heart, lungs, digestive system) first, leaving less for the extremities. Babies don't regulate temperature as efficiently as adults. Their hands and feet can feel cool even when their core body temperature is perfect. This is especially common in newborns and continues through the first year as circulation matures. The best way to check if baby is the right temperature is to feel the back of their neck or chest - these should be warm (not hot or sweaty, not cold).

Colic: inconsolable crying 3+ hours per day, 3+ days per week, for 3+ weeks (Rule of 3's). Usually starts around 2 weeks, peaks at 6 weeks, resolves by 3-4 months. Typically occurs same time each day (often evening). Baby pulls legs up, clenches fists, face turns red, passes gas. Otherwise healthy and feeding well. Cause unknown - theories include immature nervous system, gas, overstimulation. NOT parent's fault.

Tantrums typically begin 12-18 months and peak around age 2-3. Early tantrums involve crying, screaming, arching back, throwing things, hitting, or going limp. Causes: frustration at limited language/abilities, tired, hungry, overstimulated, seeking independence, testing boundaries. This is NORMAL development - baby has big feelings but lacks skills to regulate them. Brain's emotional center develops before logical center.