Ok- news flash!
Cycling... aka... riding, is hard work.
Not only are you trying to just focus on the ride and improve your endurance BUT... you have to watch for cars because let's face it, people who are driving their car DO NOT care about bikers.
Plus, you have to watch for debris in the road. Glass, nails, screws, rocks, sand, cracks (in the street) so you don't
1) fly off the bike or fall over
2) you don't jack up your bike/tire.
You have to be intelligent to ride and able to multi-task. So for all you out there driving and cussing at the bike riders, realize their job is much harder than yours and be respectful!
Oh and when that new person is on the bike, they are a little wobbly and trying to figure out their clips, shifting gears, remembering to unclip, concentrating on the debri in the road, scared some driver is going to hit them, working the 'keep riding, take a drink scenario'... that is hard work too!
That is all...