Assalamualikum!
It is naturally required of every Muslim to submit their pain and suffering to Allah & complain about it within bounds of respect and humility. This is not sort of complain like blaming Allah for any mishap, this is an expression required of every Muslim actually. If you read the complete verse i.e. “He said: I complain of my worry and sorrow to God alone and know from God what you do not” (12:86). It clearly shows that Yaqob (AS) was already informed of the fact that He will eventually meet His son Yusuf (AS) but not the timing of this rendezvous. His expression is a natural expression of every father, and his approach was that required of every Muslim i.e. Submit your complains to Allah and Allah only. One more thing that needs to be considered is the fact that Yaqob (AS) was very feeble and old at that time and He was discharged of his active responsibility as a prophet, He already did his job which was assigned to Him as a prophet. The pain that He was going through was even magnified considering his circumstances, yet, He stood by His faith and instead of creating any havoc, He submitted His complain/sorrow/woes to Allah alone. If this is not Sabr (Patience), then what is?
Coming to the question of impatience, I think you’re saying this in the context of “sabr” which is required of every Muslim. The actual meaning of this Sabr is ‘to stick to the right path with all patience and courage and to accept whatever test you’ve been put through by submitting complete trust in Allah’. However, this doesn’t mean, you can’t or shouldn’t complain your woes to Allah, its the opposite actually. Only Allah is the one whom we should all submit our complains to. Just to understand, this is the same type of complain that a child do to his/her parents while having complete faith in them and knowing that they know the best and feeling protected under their embrace, no matter what the circumstances.