There are two hikes on Oahu that I never felt the urge to do. While I'm not afraid of heights, climbing ladder-like stairs is exactly not my idea of a fun weekend morning. The Haiku hike better known as "Stairway to Heaven" requires hikers to climb nearly-vertical stairs built during WWII, now covered with overgrown foliage. The hike has been closed for decades for safety reasons but thousands of hikers have found their way to the top regardless. There have been recent talks of charging a hiking fee to pay for the restoration of the trail, however last year's storm damaged the staircase so badly that the hike is nearly unclimbable. There is a $600-1000 fine if caught on the trail but those who have done it say the risk is worth it. (photo above from @wowplacestogo).
A second hike, Koko Head Trails, is open to the public but also requires hand-and-foot climbing especially toward the top of the ridge. Friends who have done this hike complain of sore legs for the following days but boast of the spectacular view from atop. (Photos of the ocean view do look amazing.) I personally can't imagine climbing up wooden stairs for an hour...and then climbing back down the steep trailway without a hand railing. I'd be like this guy (below photo by @pbfingers) squatting myself down step by step.
Both hiking locations and parking areas can be found on google maps. Be safe.