If the stock market is all bullish and your approach is a contrarian one then you will be waiting and waiting and leaving profits at a table.
You should never go against the trend. Contrarians can mathematically never make the profits that trendfollowers can make. The reason is that in a trend there is always a net over all move in one direction. And a contrarian can never make additional profits to neutralize that net move. Trading against the trend gives also much more fake signals or signals that reverse quickly and fast.