I don't think I've ever had too much water when riding. I do know the feeling of bonking when I failed to bring along enough food/electrolyte replacement magic.
I once cramped up as I turned across a freeway acess ramp headed for the shoulder. Everytime I tried to relieve the cramp the other leg would go. I rode off the shoulder and fell into the weeds and gravel at the side. Flailing about trying to get my feet out of the shoes/pedals and relieve the cramps; up walks a CHP. Woman. She thought I had been hit and having a seizure.
I said as calmly as I could that I was fine, I just needed to get my feet off the bike so I could stand and un-cramp the muscles.
I finally got her to un-latch the Time Crit shoes and I could stand in the dirt and trash and finally get my drink bottles downed and the muscles relaxed. She kept telling me I couldn't stay there.
Once I got the legs calmed down I got my shoes back on and back on the bike and rode the mile back to my office.
When I'd left on my two hour lunch ride I was certain I had two granola bars and a couple of plastic bags with electrolyte powder in them along on my jersey pockets.
I'd forgotten I'd switched to the lighter jersey at the last moment. Luckily I remembered my wallet, and at the water stop near the dam found this out. Headed off to a not so near by 7-11 type shop. That bottle of ice cold gatoraide was good. But did not kick in soon enough or rme to avoid the cramps that lanede me in the weeds.
Those little packets of Gu I see littering the paths work for me for about an hour. I only use them as a last resort. For example on a long ride and the wind kicks up on the way back home and I've done too much chasing.
I'm lucky here to have parks with water fountains and plenty of scattered stores. I'm getting to where I know where the bike shops are so getting more fuel is pretty easy. That and I plan better. Long rides over 50 miles I wear the hydration pack with 3 liters of water and ice to start. Two bottles of electrolyte on the bike, two tubes of Gu, a couple of packets of Gummy Chomps and I'm good for 6 hours riding.
I once rode from my home in Yorba LInda California to Westminster Colorado eating only a half packet of chomps, and lots of water. Nothing else. Only stopping for gas, and the toilet, and to put on every piece of gear I had with at the top of Vail Pass. It was over 100 degrees F in the desert and light snow up high, with drizzle as I came into town 1,054 miles later.