text: 'If I were ...' is actually a past subjunctive form.  'I was ...' is (simple) past indicative.\n\nWith most verbs in English the two forms above look the same - so we hardly even notice we're using them.\n\nIt's quite a complicated area so, to understand it, you have to start with three (basic) kinds of conditional sentence:\n\n1. If he asks, I'll help him.\n2. If he asked, I would (I'd) help him.\n3. If he had asked, I would have helped him.\n\nEach of these uses a differnt combination of tenses to convey\n\n1.  A certain future action based on a likely future condition.  (I think he could possibly ask ...)\n2. A possible future action based on a less likely future condition (I think it's nlikely he'll ask)\nAND\n3.  A (now impossible) action based on a hypothetical (and now impossible) past condition.  (He didn't ask).\n\nThe past subjunctive is used in the 'If' clause of number 2.  This is NOT actually a past tense (although it nearly always looks like one in English).  It is not about the past but about what could be at any time.\n\nThe verb 'be' is the only real exception to the rule that the past indicative and the past subjunctive verb forms look the same in English.  Hence, 'If I were you ...'.\n\nMany native speakers 'smooth out' the rule to use 'If I was you ...'.  Rather than the debate about 'What is correct?' - a more interesting question is 'Is this language change in progress?  Is the fact that the difference is now only vestigal, meaning that it is in the process of dying out (like 'whom') and other vestigal grammatical constructs in languages as they change and these items become less and less useful over time?