Cool smoke can hit better, but counterintuitively, not when it is cooled through the filtration medium (water).
The biggest reason is condensation. Think about a can drink sitting out in the hot weather, and how water collects on the outside. When something very cold touches something very hot, the moisture condenses.
A very similar process happens when you filter the smoke, it passes through cold water, which condenses the humidity out of it as well as a lot of extra THC that you don't want to condense in the water.
So you end up with a relatively dry hit, that is kind of scorching to the lungs in that strange way. Because you've got incredibly dry cool air now hitting warm moist lungs and the condensation happens the other direction! Moisture from your lungs is robbed into the smoke that you just inhaled.
As weird as it sounds, the easiest way to experience this is to notice the difference between a hot filter and a cold filter, when you have a little bit of a chest cold. You'll be able to see just how much extra your lungs freak out when you take a cold hit.
All of this being said, clean bongs regularly and do not allow bacterial growth to form. Since I'm dropping three decades of stoner knowledge here, another tip is to use acetone instead of the commercial cleaners. One tablespoon of acetone beats everything. So it does a much better job than the over-the-counter cleaners, it's way cheaper, and it's a safe solvent.
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