For me I think f
to generate link labels is the most important feature for vimium. It works probably ⅔ of time for me right now, when it fails to work it gets stuck on collecting labels...
as uloco said above. I haven't been able to figure out if its going back with H
that always precedes the failure or not, but I know at least sometimes I can use hints after going back.
Refreshing the page usually fixes it.