There are things you do because they are ends, and there are things you do because they are means. Don’t confuse them.
When you’re “paying your dues,” remember that you’re doing that for a reason. It’s not because you like paying dues. It’s because you’re getting something back.
The trap closes around you because there’s a certain kind of mindset that you need to adopt in order to pay dues effectively. If you’re interning at a company and you want to maximize the experience, you need to adopt a sort of “intern mindset” full of cheerfulness, eagerness, and almost sycophantic obsequiousness. If you attend to your intern duties begrudgingly, you won’t get anywhere near the full value – that of skills, certainly, but also network, lessons, etc.
The way the trap closes is you get so used to that mindset that you forget when it’s time to shed it. You don’t realize when you’ve crossed over into someone who needs to pay dues and become someone who needs to be paid them. Someone who can advocate their own unique value.
You’re trading something when you do those things. Don’t forget the other half of the trade.