What? I'm Dehydrated.

I find when I'm really tired towards the end of my shift at work I start making really, I mean really, bad jokes. Here's a few I've made in the past few days. You tell me if I deserved a tip:

Situation 1:
I'm clearing the table of four people. As I get to the Asian man's plate of tacos I say, "Well, I can tell you didn't like this." (This is one of the jokes I say at the end of meals to get a cheap laugh, and what also makes me silently hate myself.) Anyway, the plate was virtually clear except for a few pieces of rice. So, he responded with, "Well, I didn't finish my rice but the rest was very good." And I said, "Oh yeah rice, you have probably never had this food. I'm sure it must be exciting trying it." So folks did the racial slur deserve a tip?

Situation 2:
Guy sits down and seems like he's in a bad mood. I say, "Well, how are you doing today?" He grumbles out, "Well, I just got my prostate checked." And I say, without thinking, "Do you want a second opinion?" Belittling a possible cancer victim? How much on that tip?

Situation 3:
Four old people sit down for lunch. After I shout out my welcome, three of them order alcohol. As the fourth one tells me he doesn't want anything to drink I say, "So are you the driver for these drunks?" Immediately, all the hearing aids go off and the woman, who ordered a beer, says, "You think I look drunk?" (So hard to resist.) And I say, "I saw you walking in and it looked like you were about to fall." Ah yes, insulting the old. Definitely worth the lack of tip.

What can I say, when I'm dehydrated all sensors get turned off.