Disclaimer: I do not own Adventure Time.

A/N: I couldn't sleep last night (so blame the oddity of the story on that :D) and ended up writing this short one-shot. It seems done as it is, but if enough people like the idea it might be continued. I always wondered why in the episode 'The Enchiridion!' Bubblegum was so insistent on wanting to see the chapter 'How to kiss a princess'. *cough* Marceline?*cough*

The Princess, Bonnibel Bubblegum, was not a stranger to regret. She and the emotion were old companions. Perhaps it was her scientific background that caused this bond to form?

For with science, many different outcomes can be tested, observed and the best answer chosen. Leaving little room to wonder, "Did I really make the right decision?".

Of course, you did! You had already observed all the possible outcomes and determined that it was.

Success!

And yes. Bonnibel knew that errors would be made, even under the best conditions and after long hours of heavy scrutiny.

Exhibit A: Lemongrab.

The result had not gone according to her plan. Never the less, through the experience she had gained a knowledge that had previously eluded her. And this new found logic would not betray her.

Success!

Unfortunately, and the part that caused the pink woman the most grief, life is not an experiment. Though some had often tried to convince her it could be, at times.

'Live and learn' they would say, or 'Only those who don't try, don't make mistakes'

No matter what phrases they used-

-she knew better.

Sometimes a decision had to be made that was, not planned, not logical. And sometimes that decision's effects were irreversible.

When confronted with such finite decisions, coming to a sound course of action was most difficult, even through the heaviest of calculations.

How does one even begin to truly understand how another person will react? You would have to account for the persons past memories, current state of mind, location, feelings toward the matter and so much more.

Bubblegum shivered, for she loved challenging questions such as this.

'This conundrum is what makes people both fascinating as well as terrifying.' She thought.

Something unplanned… that was what it had been.

The regret, the candy princess was feeling eat away at her stomach, was tied into a certain mischievous vampire lady. It seemed, at one point in time as though all of Bonnibel's problems could be traced back to Marceline.

Marceline, whose long black locks often became entangled with her own.

Marceline, whose glowing crimson eyes, frightened the sweet candy citizens terribly in the night.

Marceline, whose silky voice, entered her dreams causing her to wake in the night only to find her room empty.

Marceline, whose lips … whose lips were the start of all this!

A sigh, one seasoned with the wistfulness of remembrance as well as the frustration for allowing her mind to circulate back to the topic.

She remembered when the simple, spontaneous, action of a caste kiss created a decision. A decision that had to be made but-

What formula could she have possibly used?

Could she really blame herself for casting Marceline away?

She hadn't wanted to. Really, if she had, she would have done so long ago.

No!

And that is way, although the damage may seem to be irreparable, she had to find a way to make it right.

Somehow…