Why is it so hard to come up with something funny to send on text?

Why is it? or is it just me who is putting to much pressure on my self? Is it the nature of text? Do most guys find things online to send a female that would be considered funny then made by him self? it sometimes comes naturally when i text like i can say something back over a situation that sounds funny but thinking of funny things to say like jokes an stuff is hard for me.. why? says goes on the phone when it comes to jokes but i seem to always make the person laugh by my remarks..