I reserve the right to be unpleasant irrespective of the quality of day I've had.

No. It gives you no rights what-so-ever. When one feels a bad day provides the right to be a jerk it's important to understand that a jerk just feels like they have justification to be a jerk. To the rest of the world it's just a jerk acting like a jerk. Jerks everywhere are just looking for excuses to openly act like the jerk they are and feel that the have a "free pass" at being that jerk (as if there is such a thing). If one is not a jerk then they just temporarily keep their mouth shut.

Absolutely not, also, I feel being unpleasant just lengthens your misery.

Only to those directly involved it making it the bad day...

Absolutely not, under no circumstances. Why should others have to endure the slings and arrows of outrageous fortune (thanks WS)?

Nope -- unless it's to the person who was the cause of the bad day.

Sorry, the politically correct answer is no but the real answer is yes. You "get" to be unpleasant or anything else you "want" to be. You can even be unpleasant if you had a good day. Last I checked there is no "Bill of Unpleasant Rights"

I try not to be unpleasant. I can see where it might make one grumpy.

I think if your around the person that ruined your day you have the right to be a jerk towards them.

existing gives you the right to be unpleasant.
More to the point, no one is under any obligation to be pleasant.

My landlord is a super sweet and always smiling compulsive lieing manipulative control freak, who shares (gossips) the personal situations or lives of the tenants to all of we tenants. And she feels as a landlord, she deserves the "truth" regarding any question (interrogation) she puts forth. I was ill with a low grade fever this weekend and indeed having a bad day when I found myself dealing with her sweetly disguised manipulative insinuations, and I was very unpleasant towards her. . She deserved my OWN insinuations and she was thus provided a tablespoon of her own medicine. Sometimes people who go around slapping others, need to be slapped right back.

To who ?

you have no rights

Waking up gives you the right to be un-pleasant.

You have no right to be shitty to anyone who isn't being shitty to you.

You have the right to be and act how you want no matter how your day is as long as you don't break laws while doing it.

No! I am fortunate to be able to switch behaviors in a heartbeat.