I have some friends who I have no trouble talking with all day. But with the overwhelming majority of people I meet, even if we get along well, I feel exhausted after too much interaction.
Dealing with some types of "extroverts" is particularly tiring due to not caring about the weird formalities and talking around things that a lot do to seem "friendly". It's like dealing with an MBA--using pointlessly fluffy language to say pointless "pleasant" things and being so afraid to step on any toes that their statements are just boring and void of any substance. But there are also some extroverts who know how to gauge your personality in an instant and know whether you're the type who likes the fluffy stuff, or you want to jump right into talking about specific subjects.
Then there are fellow introverts, and unfortunately, it becomes obvious how bad my own personality and conversation skills are with them. Lots of super brief answers and not engaging in any discussion. But I guess when you're the one talking to an introvert, even as an introvert, it's easy to come across as one of the aforementioned annoying extroverts.