I've sat on chairs that are comfortable for only a few minutes, then start to get increasingly uncomfortable the longer I sit in them. That's more of what I meant.
That might be ok if you're a tiny shop that only really wants to do takeaway but to me, most coffee shops are a place to relax and have a conversation with someone. A chair that becomes uncomfortable after a few minutes is in direct contradiction to that purpose and indicates either hubris or ignorance on the part of the owner.