Give an opportunity that fits a class' abilit
The thief disables traps, sneaks, and picks locks. The cleric deals with the divine and the dead. Every class has things that they shine at—present an opportunity that plays to what one class shines at.
It doesn’t have to be a class that’s in play right now though. Sometimes a locked door stands between you and treasure and there’s no thief in sight. This is an invitation for invention, bargaining, and creativity. If all you’ve got is a bloody axe doesn’t every problem look like a skull?