I like to charge at a low amperage if not in a hurry. I can do this as I have a LUNA charger that adjusts from 1-5 amps. You guys with the factory built bikes can't do this i believe. No big deal, just a minor thing, I don't lose any sleep over my batteries as when they are shot, replacements will be even better! As others have said, the one thing I do is NOT fully charge it, and then let it sit for a few days. I have an inverter in my car and often charge while driving to a riding site, and I've gotten to where I can time things just right.
Being a Prius, I can also run the inverter with the car off (not running the engine that is, but actually left ON), with no danger of the accessory battery being discharged) No need for this really, I'm with the "plug it in and don't worry about it crowd", just something I do. Right now I have one 13.5 AH, two 11.5 AH, one 17 AH, and one 6 AH batteries, for three different bikes. All Panasonic or Samsung cells, and each of them amaze me with what they can do.