In terms of comfortable silence with someone I know, I'm perfectly okay with that as well. There are a select few people where I can be silent with them in their presence and it doesn't bother me, it's part of being an introvert.
Also I've had people take the initiative to exchange phone numbers only for them to get annoyed when I text them, it's why I no longer text someone first even if they take the initiative to exchange numbers unless I absolutely have to. Yeah people can catch on when you're not being authentic and honestly I've seen this happen with extroverts too, I'll observe an extrovert trying to insert themselves in a conversation and I can usually tell when their presence isn't welcomed among others but the extrovert appears to be oblivious about it.