You could have picked almost any company and made a great return in the last 6 months, assuming you did not buy at the all time highs. The market is reaching record highs right now, so it is easy to believe you have an edge as the times are good.

I would not go so far to say that simply buying companies of products you buy and understand is a viable trading strategy that will give you an edge for >100% returns. When the market is in a downturn this could be very different.