If you have swap space, it's even worse, because there's not noticeable memory pressure until you've always consumed a good bit of your swap. So I frequently find myself in a situation where I start compiling something or launch a game, and have my computer immediately slow to a crawl. Check htop, and it's always the browser I have open, taking ~13 GB of memory and another 4 GB of swap. It's certainly true that "unused RAM is wasted RAM", but that only holds when you can reclaim low priority RAM when you need to launch something new. Browsers are really bad at doing that, so they sit rather uncomfortably next to the other programs on your desktop.