To be perfectly honest, there is no right or wrong side, except as determined by a pattern or by your choice. But to avoid confusion, most people will refer to a right and wrong side rather than an inside or outside. In this photograph, Figures A and B are of Single Crochet stitches made by working in the round. Most often, people will refer to the smoother side (A) as the right side which should be the outside of the piece and the more textured looking one (B) as the wrong side or inside. And I normally prefer the A surface for my amigurumi work too, but for my free amigurumi peanut pattern, I actually prefer the B side to be on the outside as it has a texture that more resembles a peanut shell.
Figures C and D are of Single Crochet swatches worked flat and they look almost identical. However, in most cases, when a right handed person finishes Row 1, the cut tail of the yarn is on the left hand side and it will be for ALL odd numbered rows. And conversely, when a left-handed person finishes Row 1, the cut yarn tail is on the right hand side and will be for ALL odd-numbered rows. My cut yarn tails are on the bottom in each pic and I am right handed so we now know that Figure C shows that I am at a point where I just finished an even numbered row (Row 6). In Figure D, I had just turned the work to begin an odd-numbered row, Row 7.
So it is important to know what the pattern designer considers the “right” side or the outside if you are following a pattern. This will help you achieve the closest match in looks for the desired result. Fortunately, most patterns that are worked flat will indicate whether odd or even rows will be considered the right side. And most patterns worked in the round will tell you if you need to turn the work inside out or not. Confused? Don’t worry. Once you are comfortable with crochet and how it comes together, you are the boss and can decide for yourself!