There is a pleasure involved in riding a recumbent bike or trike that stays with me everytime I think of the experience. Its called the "recumbent smile". The 'smile' is well-known among recumbent riders and new riders all experience it within a few minutes of initiating movement. From the first full revolution of the pedals, one finds the exuberance of speed and a heightened sense of movement. The smile ensues and won't go away.
Riding a recumbent bike or trike is unlike riding a normal bicycle. You won't miss the uncomfortable, hard, punishing seat that regular bikes force on you. You'll sit in a reclined position, fully supported, comfortable as an easy chair in motion. Your legs are no longer pushing down in a knee-destroying movement. You'll be amazed at the ease the pedals turn and the comfort of supine peddling. Steering is also different as your arms are at your side, resting lightly on the underseat steering bars. On a normal bicycle you have to support your entire upper body pressing down on your wrists, with your nick held back in an un-natural position. I know, I've had vertebrae removed as a result of the position, as well as carpal tunnel surgery.
After my neck and wrist surgeries I was unable to ride a bicycle any longer. Niether my neck, knees, nor wrists, could take the strain any further. I was introduced to the recumbent bicycle world, moved on to the trikes - and now ride everyday, every chance I get - and I smile more than I have a right to.
That's all old news to most of us here. And the upright riders don't want to hear about it because they couldn't possibly give up any of their hill climbing prowess. I think everyone here would agree that recumbents are more comfortable than uprights.
The last recumbent rider I met had a big smile on his face, so maybe you're onto something. I have noticed, though, that in an awful lot of cyclists photos, these people all have a grimace on their faces like they're in pain. I don't ride a recumbent, but generally am having fun when I'm out on my bike, and at least smiling on the inside.
The low center of gravity gives a heightened sense of FLYING. Have you ever swayed and swooped between the center stripes . Don't we all want to FLY in our dreams, I do it with a smile every day on my recumbent.