Sometimes this can be in relation to your past. For instance, I take things really well in stride. I can "snap out of it" and "get over it" for just about anything. No upset, no grudges if someone else blew it. I do have some other weird hang-ups though, like SUPER REGRETTING when I miss catching a great photo opportunity...or video...my daughter played happy birthday at my grandma's 90h, and I didn't get my camera going in time, I STILL GET MAD ABOUT IT!!!
But anyway, as for life events where I have to adjust to what's happening and keep a good attitude, I can do that. Partially because I'm into the whole zen thing, practice a lot of yoga, studied a lot of "letting things go", forgiveness and being in the moment. I'm usually the one who can take a sucky situation, turn it around, and make it fun.
I honestly think it's because I had a pretty difficult past. Strict parents. Not much money. We had to "suck it up" most of the time regarding disappointments. Then my 20's were really tough. Living hand to mouth. Almost never getting to do the fun things other people got to do. Then I had a really difficult career that wasn't super rewarding. Lots of botched plans and hard times and no one to sympathize.it was very difficult to support myself..then some big traumatic experiences within my now defunct marriage and some other massively stressful stuff...through it all I always had my close friends with similar senses of humor to mine so we could laugh at everything-the worse the situation, the funnier sometimes! I find most of the people I know who are super funny and super resilient have gone through very hard things. Sometimes you have to laugh to keep from crying so to speak.
For things like not getting to do fun vacations and stuff..Who DOES GET TO??!!! Just joking. I guess that could be frustrating...if I ever did have a big fun plan-which I hardly ever do...
I've noticed in friends with backgrounds similar to mine where they had sketchy living situations and adversity...they are more easy going. My one friend is like M., we're happy whatever does or doesn't happen and enjoy the simple things. Her mom raised her brother and her like gypsies and they never had a nice, stable and comfortable routine to depend on.
Whereas some of my more "comfortable friends" who have really nice, secure relationships and nice pleasant lives and schedules...and always have, will FREAK OUT when little things don't go their way. My one friend is STILL angry she missed out on a trip with her girlfriends a year ago, and she does fun stuff all the time. I missed my best friend's tropical location birthday for her 50th birthday because I couldn't afford to go. She and my other friends-we've all been friends for over 20 years-all went and they had a BLAST!!!! Was I sad or jealous? No. I couldn't go. She's still my best friend and we'll make up for it.
So I don't know. Are you a generally comfortable person so these things are traumatic in proportion to your norm? Or am I way off base and you've had a tough time of things in your past so now all you want is a little comfort and fun and predictability? Or maybe it's just your nature to take disappointments really hard.
Either way I think it's natural to feel disappointed. You can grieve and bounce back at your own pace. If you want to let go of things better I have enjoyed books like "A New Earth" and "The Untethered Soul". There are a lot of other resources too for centering and being grateful and at peace with things.