I regret I don't buy bitcoin this year I was focus on the other alts. I just realized the bitcoin is on the bullish run and now the price is going to $30k USD. It is a big improvement of bitcoin from $7k USD last year January 1 from today price. You can feel the huge changes.
There's still an opportunity to buy bitcoin, if you missed to buy at low price then better wait rather than riding on the hype without assurance if the increase will be consistent.
The bullrun 2017 gave me a lesson to not be greedy. That time I missed to sell and only take profit a portion of my holdings, though its still a good amount.
Currently I made sure that I wont repeat the same mistakes again since the price of bitcoin surpass the last ath, I take advantage already to have no regrets incase the price experience a correction.