A character may take a bribe for all kinds of reasons—a desire for power or wealth, feeling entitled to more than they're earning, not believing it's wrong, or to pay off a debt. No matter how they justify it to themselves, the consequences of discovery rely heavily on the level of systemic corruption around them and how much power they wield within it.

Financial Secrets (primary), Betrayals and Violation of Trust, Illegal or Immoral Acts

GAINING WEALTH THROUGH UNETHICAL MEANS, GIVING FALSE TESTIMONY, HIDING WEALTH

BEING A BURDEN TO OTHERS, BEING PITIED, BEING SEPARATED FROM LOVED ONES, BEING UNABLE TO ACHIEVE A DREAM, LEAVING NO LEGACY, LOSING FINANCIAL SECURITY, LOSING ONE'S SOCIAL STANDING, LOSING THE RESPECT OF OTHERS

Feeling as though they can get away with anything 
Their behavior escalating to more explicit or risky crimes
Having to lie to a spouse or business partner about the source of the financial gift
Losing self-respect or being filled with self-loathing for their behavior
Avoiding opportunities that require integrity, limiting their potential for positive change
Experiencing a shift in their moral code
Becoming obsessed with doing good to balance the scales against their unethical behavior
The bribe coming at a cost, with the character having to do things they don't want to do

Hiding the extra income (via creative accounting, stashing cash, opening offshore accounts, etc.)
Creating a false narrative about the source of extra income (a second job, an inheritance, tips, investments paying off, etc.)
The character embedding themselves in a corrupt system or culture that turns a blind eye to this type of extortion or even supports it
Living modestly, despite their growing wealth
Paying off or intimidating people who could expose them