As a side-note, I wish I could give lastpass a regex or pattern or something to check auto-generate guesses against (it would be great to have a [trusted] library of these, too). I often end up regenerating or tweaking my auto generate settings a few times for every new account I create to get around this stuff.
Password managers are great until you need to log in on someone else’s machine. Especially when you don’t have your device on you. It’s bitten me before.
If you have hundreds of unique passwords, I don't see an alternative unless you're a savant or use predictable patterns. But that doesn't mean there aren't ways to get around it. For one, using a password manager shouldn't stop you from remembering your most important passwords, especially those you expect to use in other people's machines. You can take some extra care to make these important passwords easy to remember while still being secure. I could go on but everything I'd say is quite obvious.