It's easy to say that don't be greedy but it's actually very hard to control yourself from greediness. There are very few people that can control themself and avoid their loss. Most of people will get greedy by trading in crypto because it's very volatile and it can make anyone millionaire in very short time.
Its ok to be greedy to achieve your goal as long as you are doing it right but of course you must still know how to control yourself. If theres a chance of taking profit then grab it, securing your profit is one way of achieving your goal in life. The market will continue to grow at no specific time.