This is good advice but ignores moderate to severe social anxiety, depression, and many things in between. You're totally right that the worst case here is that

This is good advice but ignores moderate to severe social anxiety, depression, and many things in between. You're totally right that the worst case here is that you lose a few hours and maybe meet people you don't click with, but there's something in the mind of a lot of people that paralyzes them, or rationalizes staying in. It's not so much 30 minutes of feeling motivated or energized, it's 30 minutes of something else entirely, that you can't really psych yourself back into in much the same way that you can't "snap out of" a depressed state.