So this is something that I'm sure at least 95+% of people who look at this thread will know about, but it's something that I found out about like a year ago, and if I didn't find out about it I probably would have died by now.
This amazing feature is known as Task Manager!
This shit has helped me so many times and while the vast majority of people will know about it, this is for the small minority who don't. If you press Ctrl+Shift+Esc it will open Task Manager.
There's a few different ways this can help the average person.
If you're ever having trouble opening applications such as League of Legends, Discord, Google Chrome, etc., just open up Task Manager, scroll to wherever the faulty application is, and just click on it and click "end task". The same thing can generally be done if you can't close a program, just click on it and click "end task". This has saved me several times and while there are probably other solutions like restarting my laptop or whatever, Task manager is probably the most useful.
Another situation that has happened to me a few times is my task bar disappearing for.. some reason. If this ever happens, you can open Task Manager, scroll (it's around the bottom) down to Windows Explorer. Just restart that task and you should be set.
There are likely many more specific and general uses for Task Manager, but these are the ones that I know about. If anyone wants to help the technically braindead folks such as myself and leave more uses for it in the replies, that'd be helpful.
You're welcome 5 (or less) %! :D