Bulldog34 -- thanks for the response and clarification. I hear you about your "life is good" comment. But "life is even better" when you're a season ticket holder of the Miami Dolphins from 1971 through 1974, with a seat on the 30 yard line just 15 rows up behind the Dolphin's bench in the Orange Bowl . . . and witnessing their 17-0-0 perfect season in 1972 LIVE and when games were only $ 8 each!
Mt. Rainier -- truth be told, that was haunting me a little after nominating it. Thought I'd better double check it's day hike status. Your comment reminded me of that. A few seconds of Googling refreshed my memory that it's NOT really a day hike. So it is hereby rejected and will be deleted from the list of nominated hikes.
RenoFrank -- your nomination for "Rubicon Trail, Lake Tahoe, California" is added. I see that the 4 1/2 mile long trail also has an optional 2 mile long extension.
And I have a new nomination, sort of a dark horse candidate, so here's comes the "impassioned and persuasive" pitch. The Delicate Arch trail in Arches National Park, Utah, is only 3 miles "out and back" (round trip)! But -- I swear, it's the most fun 3 mile hike you'll ever take. The trail includes walking on slickrock. It's a nice walk, certainly quite scenic, and then dramatically escalates at the end, as you round a corner and see -- and see only then -- Delicate Arch (the symbol on Utah license plates). It's indescribably inspiring and you can walk up to it and under it, with a large sandstone bowl below it. (Watch your step -- DON'T tumble down in to it.) You then sit down between the bowl and the arch, with the space within the arch framing snow capped peaks, and you remain seated for an hour, wishing all of life could be so serene. (And if you're as lucky as I was, you'll encounter a Rocky Mountain bighorn sheep in repose only about 15 feet from you on the return to the trailhead -- I was told a sighting like that was quite rare at the time.)
