Did you make sure to close Firefox before shutting down the computer?

Firefox doesn't like to be forced to close down by shutting down the computer.
You should always make sure to close all open programs or choose the hibernate.

>>Firefox doesn't like to be forced to close down by shutting down the computer.<<

but why not? I think it should be able to handle it.

You are basically crashing Firefox by keeping it running when you shut down the computer. In Firefox go to File->Exit to close Firefox before shutting down.

Crashing Firefox can also potentially damage your Firefox Profile settings.

Firefox usually needs more time to close shutdown completely than the OS is allowing when shutting down, so it is quite possible that Firefox is still in the process to save and cleanup all its data and gets interrupted before having finished properly.

Is there a way to tell it to stop being embarrassed and just reload my tabs automatically?

Just make sure the Firefox process is finished running completely before shutting down OS and mare sure "Show my windows and tabs from last time" is selected in Edit > Preferences > General.

If you close Firefox by way of File->Quit and open Firefox is should then start with all windows and tabs you you had open when you closed Firefox before. No need to purposely crash Firefox in order to resume where you left off.

If Firefox is running when I want to shut down I exit Firefox first and then go about closing other things as Firefox can sometimes take the longest to finish running especially if it has been up running for a good while and I have been viewing Flash videos.