It is not entirely an horrible thinking and certainly, a lot of us had so many not so true ideas at the time we got started in our bitcoin investment but overtime, we have learnt a lot about bitcoin on how investment journey. from an elementary point of view, bitcoin is a volatile asset and by that, it means that within a short timeframe, we can see some up and some down which agrees with your assertion that bitcoin price does not continue to go up and up and up. but what if we consider it from a long term perspective looking at it from how far bitcoin has come? wont it be right to conclude that bitcoin has been going up and up and up to this point we are now regardless of some correction that has happened occasionally?

Bitcoin does not take a linear part and that is where short term traders or gamblers always get it wrong but in the long run, you can see what looks like a linear movement as bitcoin continues to witness ATH upon ATH. every time we see new ATH it shows that bitcoin has gone high than it did in the past.
sure. bitcoin investment requires planning and investing with the right strategy as well as identifying the stage you are in as an investor and what you should be doing at that stage. for instance, if you are still in your accumulation phase, the only thing that should be your concern should be strategy that you can set up that will help you accumulate and get to your investment goal fast enough. selling should never come to mind in that phase until you have attained your goal and regardless of the short term market reaction, you know better that it can only last for a short period of time and so, you are never worried because of short term market sentiment.