Of course, the carefree Kelso may not get as angry as some of That ’70s Show characters, such as Eric’s (Topher Grace’s) stern father, Red Foreman (Kurtwood Smith). However, fans love the strange sound Kelso makes whenever he gets angry or offended. The noise sounds like a short bird screech or snort, and Redditor u/thinkb4youspeak described it as “a masculine version of a sigh of indignation”. Fans on Reddit generally found this detail of Kelso amusing. Even if it wasn’t that funny, his angry sound gets funnier every time he does it. The audience is looking forward to this climax, and it’s satisfying when the joke continues again. Sometimes things get even more fun when the audience finds out why Kelso is so upset.
Part of the reason Kelso’s angry noise seems so funny is because it’s in the realm of what he would do, but yet unexpected in other ways. It’s more like Jackie’s (Mila Kunis) reaction. redditor u/JustSomeRandomGX noted that Jackie actually makes the same sound when he finds out that Kelso is dating Lori (Lisa Robin Kelly/Christina Moore). So maybe part of what Kelso loves about this quirk is that it shows how easily he picks up on Jackie’s habits.