there are no such a thing,Hold or Regret,both of them can happen to us.
for example,
people Hold Bitcoin when it was around $1 and they kept it until it reached $10,afterward they sold and wait for it to retrace.
in the end the price did not go down and kept moving up,
they're regreting it,they were regret to sell it that low.
Regret is an emotion,and it can happen to us.
so Hold or not,it won't change it and it will always affect us no matter what.