Good morning! I know that soon it will be noon but now it's still 11AM so I can still say good morning. So, what have you done so far? I will enjoy the rest of these few hours (at least until church volunteering time) to replenish my energy which is totally drained yesterday.

1. Blame in on the personality

I guess this is where extrovert-introvert character plays out. Some people may have a different tolerance level toward socialising and networking. For instance those who have more extrovert genes in their trait would relatively last longer socialising because they don't get drained from talking to people. In fact, some of them even got energised talking to different people. Whereby, those who lean toward the introvert characteristic would behave the other way around as they tend to get energised from spending time along with their thoughts and interests.

2. Different level of experience

Socialising is after all, a skill for survival. If you are born in a family which is not very social (e.g. not very interested to come to neighbour's kids birthday party or big family social gathering), you will be more likely to have a lower level of experience in socialising.  This experience does not have to cater to a socialising in general. The people who you will socialise with matters too. For example, someone may have no problem hanging out with their close buddies but get fatigues really quickly at a hectic office party as they are not as used to the latter.

3. Anxiety in social situations

Being nervous is physically and mentally draining too just by itself. People who force themselves to be in situations where their anxiety appears, will obviously get pretty much drained after the whole affair. It's like being forced out of your comfort zone. I don't mean that it's bad literally. I mean we are human which is social creature, by nature, so it's good to face our fear once in a while, I guess? I would probably do this to myself once every quarter. 4x a year is more than enough for my tolerance level. XD