Secondary Benefits
Sometimes you'll find that no matter how much you tap, something just refuses to clear.
Often, this will be because there are secondary benefits to keeping the issue around.
In other words, there are good reasons why we don't want to shift it.
An example was given of a woman in a wheel chair (she had a sore leg, or something). No matter how much tapping they did, they couldn't shift her pain. Later she admitted, "Why would I want to get out of this wheelchair? Everywhere I go I get priority treatment. People look after me. I get the best tables at restaurants, it's great!"
If you find yourself struggling, asking yourself what benefits there are to having the problem will shine a light on this sort of thing.
Once you see the secondary benefit, you can tap on that directly until it's gone. Then go back to the main issue, and it will be much easier to clear.