I made a silly mistake
I took my bike out of my car today and reattached the front wheel. I failed to notice that the brake was rubbing against the wheel. I rode it with the brake rubbing against the wheel for 10 miles before stopping for food, and then I noticed my front wheel wasn't rolling freely. All that time I was wondering why I was going slower than normal, I was averaging 11 mph. There was no wind and it was flat, so I thought I was bonking and needed to eat something sugary. I fixed the position of the brake and that made a world of difference. The next 20 miles flew by and I had an average speed of 15 mph for the trip including the first 10 miles. I feel so stupid after making that mistake. It's like driving with the parking brake on and wondering why the car is accelerating slowly, which I've done before too.
You an extra workout & experience at the same time. Dude, you're multitasking.
Long Distance Cyclist
These things happen. No big deal.