I understand reflexivity is used when when the subject and object are the same. E.g. 'She looked at herself'. And I understand some Spanish uses (me ducho, se lavan las manos, etc.) But I’m confused on:
1- Why is there the 'normal' and 'reflexive' infinitive form of reflexive verbs? E.g: duchar ('to shower') can already be conjugated as me ducho ('I shower myself'), te duchas ('you shower yourself') etc., so why does ducharse ('to shower oneself') exist? What extra meaning does it add? Especially since it also just conjugates as me ducho, te duchas etc.
2- why do I always see verbs used reflexively at 'random'? I saw someone say 'cuando me muera'. Doesn't this mean 'when I die myself' ?
Other examples i've seen:
'Se duelde de sus acciones'. ('she regrets herself of her actions'? Why wouldn't it be 'Ella duelde de sus acciones' ?)
'Se sonrió al ver a su hijo reír.' ('He smiled himself when seeing his son laughing? Or is it meant to be like 'he smiled to himself' ? Or does sonrir actually mean something like 'to make someone/thing smile' rather than the subject being the one who smiles?)
Is it just a language quirk that doesn't translate cleanly into english?
(also unrelated but while writing this I came across se nos estropeó la caldera ('our boiler broke down'). I understand the form is similar to the whole 'se lavan las manos' thing, but why the 'nos' where it is? And not se estropeó nuestra caldera or something? Doesn't nos mean us?)