I wish I was/were

"Were" used this way is called the subjunctive mood.

This mood is used to express a wish or possible situation that is currently not true. It's usually used with words like "if" and "wish".

Other examples:

"I wish I were a sea cucumber."

"If I were you, I would eat less bacon."

Problems with the subjunctive, for non-native speakers of English, may arise because English doesn't have a subjunctive mood 'proper', so to speak, so it has to 'borrow' verb forms that usually belong to the indicative mood.
The "subjunctive WERE", as Randolph Quirk calls it, is hypothetical in meaning and is used in conditional (type II) and concessive sentences and in subordinate clauses a

so in what cases do you use "was"?

Perhaps I caused some confusion here? I'll try to fix it.

Melanie,
when you are using the simple past, you use 'was' for the 1st and 3rd persons singular, and you use 'were' for the other persons:
"I/He/She/It was here yesterday."
"We/You/They were here yestersay."

Now, in conditional sentences or in any other instances in which the subjunctive mood is needed, y

"I wish I/he was..." is very informal. Many people would pass judgement on a speaker's education on hearing them say this.

I'm not trying to start an argument with anyone, but I suggest that people don't even bother to learn this version of the subjunctive. If you know it, forget it. Just keep in mind that some people will use it out of habit or because they don't know better.

*** bless you for that post, Ryan!!

I try to be very careful when I post about usage because I don't live in an English-sp

I suppose that the best advice would be to save the subjunctive 'were' for formal writing and ESL tests. Were one to use it elsewhere, one could seem pretentious.

Miriam,

Glad to help. But really, your post covered everything quite nicely. I was merely pointing out a pitfall of using informal language. Anyway, English wouldn't be English if there weren't many different ways to say the same thing.

Note to students: Nestor's got a nice little joke nested in his post...Don't avoid the correct form.

Thank you Ryan, Mariam and others, for the very informative explanation. It was a good resolution to this question howering in my mind for years.

for I and YOU pronouns...in rules of using is and are....singular nouns/pronouns normally follow the linking verb in singular form. However with I and YOU, even if they appear to be one person. I and YOU are exceptions. the proper grammar for it is:

"I" ---> the present tense for "were" is am. "were" is in the past form.
"YOU"---> the present tense for were is are.