Don’t argue from anecdote
By which I mean exactly what I say — personal experience is irrelevant. I learned this myself much later than I’d prefer to admit, and it turns out that it’s terrible form.
The problem is that too many offer a personal narrative drawn on their own experiences and then go on to generalize, based on that impression. This not only introduces (often overwhelming) bias, but better still, the only way to validate that kind of claim is if you can show the generalization really does apply to the whole.
Of course, folks do this all the time and it isn’t quite the same as tu quoque or the “no true Scotsman” fallacy. But it also introduces cognitive dissonance by artificially limiting the sampled data.