Lots of people consider the Mist Trail a challenging hike all by itself. Sections of it are steep, and all those steps carved into the cliff beside Vernal Fall are a wakeup call for anyone's quads. Plenty of travelers consider this a day's work.
You, however, the intrepid Half Dome hiker, will summit Vernal Fall before breakfast and Nevada Fall before lunch. By the time you're sitting atop Half Dome, your passage up the Mist Trail this morning will seem like it was another lifetime, back when you were a callow, unworldly sort of adventurer who'd never faced the Half Dome cables.