I'm glad that others have the same experience, and it's not just me
It's interesting how emotional attachments to certain coins can take precedence over logic, even when you know that it is happening. Especially with the first coins that you bought - even when it is clearly logical to sell, there is still the history of "this coin has given me more profit than anything else".
I have improved at trading over the last year, but if I ever try to trade my favourite coins I still get a little panic when I see the price immediately going the wrong way. I think this is a part of the problem as well - the coins that I like the most, I am worse at trading, which is another factor that prevents me selling them.
But I am determined to master it in the end!