Regret..!

one of the confusing questions that always comes to my mind & keep bothering me sometimes ...!!
Is REGRET a human right?...& i mean to regret an action or a decision without being ungrateful to Allah & without being overwhelmed by the severe feeling of guilt?!

coz whenever sb complains about sth & say that he regrets a certain decision almost ev1 blames him for thinking that way & just say "that's how Allah plans our lives ,..& mayb it's good for u ,..so dnt regret coz u r unthankful that way....."...or they say "didn't u pray "esti7'ara"?....then believe that whatever path u've taken ,..it's the best inshaAllah"....etc.

surely i totally agree with all that,..& i do believe in it ...so where's the problem?!!!!
the problem that i agree to a certain point,....but i keep thinking about some confusing points...!!

Allah gives the human the freedom to choose in certain points in life ,...so the person is responsible for his actions & there's a chance to make wrong decisions ,...& that's y there's the accountability issue or the (Thawab & 3ekab),... & as for the "esti7'ara" issue ,..i'm not sure but i guess it's not a compass or a 100% indication coz still the human mind & some other factors may dominate & direct the person,... so i believe we can't just consider it a thing to hang every decision or action on it ...!!

so thinking that way make me reach the conclusion that :
if the person has the chance to make both right & wrong decision than it's valid to regret his actions & learn from his faults without being ungrateful to Allah....!!
i always try to rethink to find out whether i'm right or wrong.....but after all i keep thinking.....!!

i know it's a complicated issue,..& mayb i couldn't explain it clearly ,...but that's how it goes with thoughts ....!!!