The purpose of a piece of writing is to communicate an idea. Some ideas are simple, some are complex. Most language arts teachers discourage the use of semi-colons because they encourage sloppy thinking and clumsy turgid expression. All complex ideas can be broken down into simpler components, which if placed in the correct sequence enhance the exercise of communication. A writer who avoids the use of semi-colons therefore usually finds that he is forcing himself to think more analytically, and express himself more clearly.

Personally, I use semi-colons a lot, either because I'm lazy, or I'm in a hurry, or I don't believe the idea or the piece of writing I'm working on merits the time required to optimize it as a piece of expression.

It's the difference between slapping all the eatables in the fridge on a single plate, which goes into the microwave before the 8 o'clock show begins, on the one hand; or spending an hour or two preparing a fine meal of several courses, with a clean white tablecloth and flowers and candles and wine and desert, for an attempted seduction, on the other. (See what I mean about the semi-colon?) I've thought about making the latter epicurean effort, but have never done anything more than going to a restaurant, which probably explains why I'm still a widower after more than a decade of living alone. It spoils you. Overuse of the semi-colon does the same thing