You're absolutely right. Certain percentage of a person's lifestyle can be easily known from their social life interactions. Though it might not be the best means to evaluate a person's lifestyle, but still counts.

I know few guys in person who are serious about life and work but posts memes almost everyday. The memes are mostly dark humors or just very funny. This might portray them as very jovial or a person who jokes around or just unserious. You can't tell everyone who exactly you are, people have different opinions and see from different perspectives.