This is truly bike-related...really...you'll see.
Why is it, the more you know about bikes, the more you want to tweak every little thing on it to make it better? Why is it, also, that 99 times out of 100, once you tweak something, you can't ride as well as a 10 year old chimp on a unicycle?
Case in point:
Decided to get an FSA Compact Crank for my bike to help with the hills. Put it on, and immediately my average speed dropped by 1-2 mph for hills I was doing with a standard double. I threw my double back on...trained with that for awhile...and remembered I had the compact and "wouldn't the hills be so much nicer with easier gears" and switched it out again. The hills still suck, I'm just slower going up them. Switched it back...switched it back...and switched it back again.
This isn't just switching out cranks, here...it's a bottom-bracket (megaExo/isis) switch as well...plus the front derailler adjustments. Makes me wish I just never got the compact in the first place.
Other cases that cause endless fidgetry:
My tried-and-true Brooks saddle looks like an outhouse at the Parthenon...got a Specialized Toupe...lasted for all of 10 miles before my ass gave away. Put the Brooks back on. Will probably put the Toupe back on in the near future.
I HATE my Ultegra one-sided Look-style pedals when starting at stoplights. I always end up standing on the bottom of the pedal and slipping only to wrack the berries in the middle of the intersection with everybody watching. I got some Speedplays, and LOVE the two-sided entry, but my feet just can't take them. Hot spots galore, seemingly regardless of cleat location. Got Lemond LeWedges...helped a little, but still hurt too much, so I'm back to my Ultegras. Comfy feet outweigh wracked 'nads, in my case. I've switched between these two pedals, Oh...about 6 times now.