Let's start with the confession, shall we?
Coincidentally (above), I've just introduced you to a comma that's not a splice. You see, two equally grammatically correct sentences should not ordinarily be separated by a comma, without the "FANBOYS" (for, and, nor, but, or, yet, or so). But, occasionally, when a sentence is short, you can get away with it.
OK, I know you want the confession: I have been stewing a bit over this area of my Web site; after all, I'm an aspiring copy editor whose working double time to be great, not mediocre. I'm not Bill Walsh, or Strunk, or E. B. White. I'm definitely not Karen Elizabeth Gordon, but darn, I'm working on it!
Some like it hot, some like it cold (another grand example).
Here's a splice: Jack and Jill bought a new 27-inch (small for this day and age) TV, they sat down and watched their favourite comedy/romance: You've Got Mail.
Who cares?
Me, of course. Hopefully you will, too.