[throes_death]

Devils advocate here. Hi!

Is it necessary to excel to be successful and/or happy?

[mLuby]

Yes, but the thing you're excelling at may not be what it seems at first glance.

It is possible to be excellent at enjoying a simple life (most of us are terrible at it).

It is possible to enjoy being terrible at something because it's fun(ny) or reminds us of our youth.

[ljf]

Said the happy and successful person. /s

[abtinf]

Yes, within the bounds of your ability.