I am not sure that I understand your post. Are you asking what are conversation road blocks that others have or what your possible road blocks could be?
I can only offer what examples of my own issues... I know for me that the setting is very important when having a conversation with anyone. If there is too much going on around me, I cannot keep up for long. Too much would be people moving around, multiple conversations, someone with strong cologne, those damn halogen lights, overhead music changing from one song to another... the list goes on... but all of these little things are very taxing on me and drain my battery faster than I can recharge the damn thing and after awhile I just shut down. I am not much of a drinker as it makes me somewhat queasy, but I have been 'intoxicated' and been able to roll with conversations for longer amounts of time likely due to my dulled senses, but it still catches up to me. As awful as it is, if I do not find a particular subject of conversation interesting, I have an even harder time keeping up with it. It is like my give a damn to even try is already half used up before I start, leaving less in my reserve.
I try to not engage people in meaningful discussion in public places and if I have to, I try to engage them in a calm and quiet setting. I also try to be calm before I have to go places with people... where I am to start makes a huge difference on when I will be done. I have no idea if this helps or was even what you were looking for...
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"...don't ask me why it's just the nature of my groove..."