Inserting the hook into the front or back loop

Dear users, dear authors,
Does it make a difference whether you insert the hook into or under the front or back loop when crocheting?

Oh yes, because depending on the crochet project, the loose thread will then be in front or behind—or on the inside or outside—if you need to pick up stitches there later.
Often, however, it’s just used for an edge, which then naturally bends forward or backward accordingly—for example, to more sharply define the transition from the increase section to the steady part of a round piece, such as when I want to crochet a thick disc rather than a sphere.

....this is very important when crocheting a mosaic pattern. In this case, single crochet stitches are always worked into the front loop only, and double crochet stitches are worked one row lower into the exposed front loop. This is how the pattern is created. 

Each round/row is crocheted with a single color. The reverse side is simply striped... 

Nonsense... Single crochet stitches into the back loop...
I really should try to get some sleep. It’s not going very well right now. My dog has a heart ultrasound appointment on Monday, and that’s really weighing on me... 

You can also create patterns using the front loop and the back loop, for example, my pumpkins.