A position up three units and closed at one feels like a loss of two, even though it is a gain. The peak is the strongest reference-point in trading and it turns good trades into painful memories.
Two separate problems hide inside it. One is emotional accounting, which is fixed by measuring against entry and risk rather than against the best price. The other is genuine: if you routinely give back most of the move, the exit rules need work - a trail, a partial, or a defined target.
Decide which you have by measuring. Compare realised R against maximum favourable excursion across fifty trades. If the gap is large and consistent, it is a mechanics problem, not a mood problem.
Related: reference-point, greed, runner, take-profit