极 (traditional 極) was the ridgepole — the highest beam of a roof, the wooden limit of the house. Highest point became utmost degree: the pole, the extreme.
极 pushes to the limit: 好极了! (fantastic! — the V+极了 pattern turbocharges any adjective), 北极/南极 (North/South Pole), 极了 everywhere in enthusiastic speech. Philosophy claims it too: 太极 (Taiji, the 'supreme ultimate' — yes, the slow-motion morning exercise carries the most metaphysical name possible). From rooftops to poles to 太极拳 in the park, 极 marks where things max out.
The ridgepole 木 — as high as the house goes: EXTREMELY.
太极 'Supreme Ultimate' — the cosmological limit of yin-yang — is also grandma's 6 a.m. park exercise. Range.