The gray line is my “standard” trend estimate. I consider it quite reliable but it is deliberately conservative, requiring clear evidence of changes in trend before it will turn.
The chart below includes a more sensitive trend estimator, nick named “Ready Red” which is quicker to detect changes in trend, but it is also more subject to being misled by a few outliers. “Red” eventually returns to the gray standard line, but it is quicker to show a change in trend even if it is sometimes fooled. Use with caution.