Don't fall in love with a coin, has probably been best advice i have heard. That means that if you have strong emotional bond with your bag when it's going up, you don't see what's happening, because you stay convinced that it's the next ETH or something.
It is when a person starts confusing their luck for skill. The coin that they invested in pumped a lot, and to them this must mean that it is going to be a big thing. Of course the things don't work that way and most of the time it is just pure luck and timing, most of these coins die later on.
I doubt that anything here is skill. At least i haven't yet seen anyone skillful in here, whose profits couldn't be explained by dumb luck. Sure, sometimes you catch coins with good fundamentals in right time, but just finding those and timing them right is a skill. And even with good fundamentals you can fail. And by definition any TA is based on probability, and even if that probability is high, usually those mean profits that are low in percentages, which can be taken away with one fast crash.
It's pretty much impossible to prove that you are making money because of skill, because if you try to recreate some investment that brought you 100x or more, i will guarantee that 99+% of those attempts will fail.