I think there is often tension between DRY and "thing should do only one thing." E.g., I've found myself guilty of DRYing up a function, but the use is slightly different in a couple places, so... I know, I'll just add a flag/additional function argument. And you keep doing that and soon you have a messed up function with lots of conditional logic.

The key is to avoid the temptation to DRY when things are only slightly different and find a balance between reuse and "one function/class should only do one thing."