Startups have their own pathologies, but I'm going to point you that if you think "perpetual crisis mode" is somehow a big-company problem, you're going to be disappointed. Especially at a startup that isn't profitable yet, you're essentially continually in "crisis" given that if you don't achieve profitability or sale, you're going to be out of work. It's a whole different grade of pressure from a big company where "crisis mode" rarely actually results in anyone losing their job.

Also, re this comment "The prevalence of social bubble-worthy companies whose value propositions are little more than "cat pictures" suggests an inflated sense of self-importance among the founders, and I can't expect to keep my level of enthusiasm in line with their irrational exuberance." ... I think you're over thinking this. There are silly startups because people (for one reason or another) are willing to invest in them, and generally those folks aren't the founders. Whatever startup you go to, you'd better believe in what they're doing, because you're going to be taking a huge financial risk and going through a lot of stress attempting to play out that belief.

If you don't believe in a startup, don't work there - but also don't denigrate whatever vision they're trying to implement, at least respect that they're trying.