Ever hit that annoying insufficient balance error when trying to send U out? Yeah, I was confused too until someone explained the network fee thing. Turns out when you withdraw, the blockchain fee gets taken from your balance first, so what you see available isn't actually what you can move out. That's why you get the insufficient balance message even though your wallet shows enough. The fee amount varies depending on the network you're using, so sometimes you gotta leave a little extra buffer just in case. Wish it was clearer upfront though.