に堪えない => not worth doing; can't do; cannot bear doing ~ N1
たまらない => can not bear N2
Emphasis on degree
に堪える => to deserve, be worthy of, to have value N1
… となったら => If... N2
Condition (hypothetical condition)
たまらない => can't help but; dying to; extremely ~ N2
といったらない/といったらありはしない => Extremely A, Very A, A beyond description N1
Degree/ Level/Amount
くらいなら/ぐらいなら => rather than (do …)​ N1
~ ば/たら~かもしれない => If only... then... N2
Regret
~ ば/たら~かもしれない => If...then maybe... N3
Condition (hypothetical condition)
といいなあ/たらいいなあ/ばいいなあ => it would be nice if; should; I hope ~ N3
たなら => if; in the case that ~ N3
Condition (hypothetical condition)
せられたい => Please..., Let me... N3
Order