I just relearned that lesson last night when I raised my expectations on a pharma and at close last night they announces mixed results on phase III trial... could have sold at 30% profit or more several times, but was expecting a double. Went from 3.23 before halt at the bell to reopen after hours at 0.09. Recovered to 1.74 overnight and hoping the good part of the mixed news gets me close enough to good...
... always go with your instinct when it's time to sell. You always miss the money you lost more than you miss the profit you might have had.
Any sale in the green is a successful trade IMO. FOMO and looking back at your "failures" isn't productive.
What I try to do is a day trade a hot stock and then only keep my profits invested if I believe in the company. Right now 75% of what I have reinvested in NKLA is profit from day trading it a month ago.