There is indeed such a thing as luck -- external things working to your favor or not. (Rationalists, like everyone else, hope that these things work in our favor.)

I think "hope" is a mostly meaningless and sometimes harmful concept that should be suppressed (similarly to the urge to rationalize, or to care about sunk costs). These things have their value as heuristics, but it's easy enough to evaluate their queries explicitly instead of unreflectively following the emotion. (For example, hope makes salient the expected value of highly valuable unlikely things; rationalization protects you from blame; sunk costs motivate continued planning of ongoing projects).