I admit to buying bottled water fairly often. Going to class, on the road...etc.
I do try and reuse those water bottles as much as possible (usually till they get stinky) and recycle the bottles but more often than I'd like it to happen, I lose the bottles during transportation. They fall out of my bag, I forget them, etc.
I'd say I lose about 1 bottle every two weeks. If I had to buy an empty container at a dollar+ and had to find a dollar store to do it then find a water fountain instead of running to just about anywhere and buying a case for $3.00, well it's just not good sense for when I need water.
I mean, it isn't just slightly inconvient, it is really inconvient. I remember back when bottled water was never there before, I'd just end up buying coke. In any case, bottled water is healthier than coke.