I am a parent of 2 growing children. When they were little babies (whilst there were many challenges and sleepless nights) one of the many bright spots of looking after them was (and still is) hearing their laughter. I still remember the first time I got a real "belly" laugh out of my first born; it was magic! All I could think about for the next few weeks was how to recreate that sound and the joy on the little one's face. The other memory of laughter that really stays with me is that both children at times would laugh in their sleep. I get up early to read and would often be pleasantly interrupted by the giggling of a soundly sleeping child that was not even a year old. I would think "what kind of dream does a baby have to laugh about?!"
Hearing my children genuinely laugh is one of my favourite experiences and a genuine laugh is not easily faked. Learning to fake it convincingly is a major step for actors, who are often coached to get the right effect. It truly is one of the genuine pure pleasures of life to be able to make someone (especially someone you care about) laugh genuinely and whole-heartedly. It is also a significant opportunity for you to bring satisfaction to someone else, allowing them to hear you truly laugh at something they have said or done.
As kids, my brothers and I had this weird unsaid psychological game (or at least in my head we did) where we would do our absolute best not to give each other the satisfaction of letting them make us laugh. It was a funny sort of competitive thing - "I can't let my brother know he said something that I actually found funny!" While I think some competitive spirit turns out better men (probably women too), we probably missed out (again at least I did) on some bonding experiences there - something which could have eventually carried over into adulthood.
Laughing at someone's attempt to tickle your funny bone (again, it must be a genuine laugh) even when you don't want to give them that satisfaction, is actually a great act of generosity. It is a powerful connector for people in ways that words can't be. It shows a slight vulnerability in that it conveys a sense of respect to whomever you might be conversing with. Who knows what kind of opportunities that could open up?
Don't deprive people or yourself!