Need help understanding: "人生要就不忍，不然就請你一忍到底。"
&quot;要就(X )不然就(Y)&quot;  means &quot;either (X) otherwise/ or (Y)&quot;
(X) and (Y) are the two options for you to choose.

&quot;要就(X = 不忍)，不然就(Y = 請你一忍到底)&quot;
&quot;you either not restrain yourself (option X), otherwise please restrain to the very end (option Y).&quot;

非凡之人做事(要就)不做, (一但) (要做) 就必要做到乾淨漂亮

Exceptional person (either) not act, (once)(decided to act) then  he must do it cleanly and beautifully
一但(once) is omitted
&quot;一但要做&quot; (once decided to act) presents a different option than the first one, therefore the meaning of &quot;otherwise&quot; is implied. The sentence could then be interpreted as &quot;exceptional person either not act, otherwise, he must do it cleanly and beautifully&quot;
The two options are &quot;不做&quot; (not do it) and &quot;做到乾淨漂亮&quot; (do it cleanly and beautifully)