Here's my "feat tax."
Sam's Wham Bam
You know that it's never enough to just hit someone. You feel the need to hit someone with the person you just hit.
Strength 16, Power Attack, Improved Bull Rush
When you make a Power Attack, you can forgo dealing the extra damage from Power Attack to move your target (if your size or smaller). The target must pass a Balance check (DC 10 + attackers STR mod) or be moved in any direction 5' for each -1 penalty to the attack roll with a success only moving the target 5' / -5 penalty (rounded down). If the target would be stopped by another creature, both creatures take damage.
If using a two-handed weapon, this damage is equal to the extra damage you would have dealt from the power attack plus one and a half times your Strength modifier (initial target would then take the extra damage from Strength modifier twice). If you are using a one-handed weapon, the damage is equal to the extra damage you would have dealt from the power attack plus half your strength modifier. If you are using a light weapon (to include unarmed strikes), the damage is equal to the extra damage you would have dealth from the power attack.
If the target would hit a solid object, treat the impact as if you had made a sunder attempt and the initial target takes any damage the object does (after adjusting for the object's Hardness).