For years, I used an email and Usenet signature highlighting my fandom of two championship-caliber sports teams/individuals. I did away with the personal email signature at some point, and changed my Usenet signature when I started using a spam retarder in my email address in the "from" line (because at the time, spammers were harvesting email addresses from Usenet to target their recipients.)
I use a work email signature that includes various ways to contact me (email, phone numbers, social media accounts, agency Web site, etc.) and a different signature on my phone Outlook account to call attention to the fact that it came from a mobile device where typos and brevity are often common.
Here, my signature is Grumpy Cat because she's my spirit animal, and my personal text is a statement that I'm comfortable in my own beliefs and actions as an affirmation of my faith; that I sleep well at night with the opinions I have and the causes I support and oppose. "It Is Well With My Soul" is one of my favorite hymns.
Some people change theirs up frequently for whatever reason. Don't feel pressured to have one, or not have one.