I block hard a lot too. Particularly on F words recently. It feels like the block is a symptom of the disorder to me because it feels so engrained in me, but there are times where I get pissed off and need to just finish my sentence so I push through the block and stutter. So for for me, at least, blocking is because I don’t want to stutter or look like I’m dying trying to pronounce a word. Not that I literally can not say it. I just can’t say it without stuttering hard as hell and making myself feel bad :).