This may sound bad but please consider that I'm truly uncomfortable with these kinds of activities.
I'm a junior software developer, I work with an amazing team and I get along with everyone. I'm very thankful for the knowledge that everyone has shared with me.
However I do not feel the desire to have anything but a formal business relationship with my colleagues. Colleagues do not push for informality but management does push for "team building" activities, which to me seem really informal and unnecessary(think of beach volleyball). All my colleagues seem to understand that not everyone likes these kind of get togethers and some do not like them themselves but they find excuses not to go.
I've so far been honest with my manager about the reason I do not go to events with activities but I'm facing increasing pressure to go....
My performance and work is good, "exceptional" even, if I were to quote that specific manager. Which adds to my guilt when declining his invitations.... I'm pretty sure they cannot force me to attend since these activities are always outside of working hours, but how do I stop these requests/demands for my attendance?
All advice is very welcome.
EDIT Edit to the original question (in reaction to some welcome comments and answers, thanks!) to make clear that I do not skip all meetings outside working hours. Especially dinners or talks that do not require me to engage in some kind of activity I will attend. My colleagues know this and seem to respect my honesty, however my managers increased their efforts to make me attend.
To the point that one of them will walk into our shared office after I declined an invitation and be like "ConfusedEmployee you don't like X I'll make it Y think about it please!". Which on one hand makes me feel apreciated since to me it seems that his intention is good hearted. However it also gives me increasing guilt to turn it down a second time and besides that I also do not wish the activities to be changed for me since I will never truly enjoy them, so it seems more logical to me to find activities that my colleagues will actually enjoy.