Assume $D$ is a directed set such that there does not exist $d\in D$ satisfying $d\geq d'$ for all $d'\in D$.
Can we always find a sequence $(d_n)_{n\in \mathbb N}$ such that $d_{n+1}\geq d_n$ for all $n$, and such that there does not exist $d\in D$ satisfying $d\geq d_n$ for all $n\in \mathbb N$?
Is the result true? Is there an easy counter-example? Or only under some assumptions?
Let $D$ be the first uncountable ordinal.