However, by far the most infuriating (and one I run into frequently in my line of work, hence the anger) is when you are trying to get the language running on a platform for which binary bootstraps do not yet exist.
Portability matters. If you want your language to be useful and available to as many people as possible, why would you seek to artificially limit the number of platforms it can be built on, just so you can avoid writing the bootstrap in C? I'm sure there is some amount of pride on the part of the language author when their language can bootstrap itself, but it certainly isn't a pragmatic decision.
It's especially frustrating when the bootstrap requirement itself changes so that only very recent versions of the language are sufficient (e.g. GHC), leaving the porter to have to reach back into the archives and carefully plot a path through building multiple versions from the original C-based bootstrap until they finally get to master.
This is painful, painful work, and then has to be done all over again for e.g. 32-bit vs 64-bit. It doesn't have to be like this.