Other Uses for Gustar
I am currently enrolled in Spanish I. I am always asking my teacher questions, because I'm always wanting to learn more about the Spanish language than the few simple concepts which we cover in class. One day I asked her about the conjugating of gustar, but she was a bit annoyed with all of my questions and told me not to ask any more of them!
Here is what I know so far.
"Mucho gusto" roughly means "pleasure to meet you".
[direct object pronoun{s}] + gusta(n) = [someone{s}] like(s) something(s)
One time she told me that you will never conjugate gustar, because it is always used in the infinitive form. Clearly, this is not true, or else we wouldn't say "mucho gusto".
My two questions are:
1. Why do we conjugate gustar into the third person singular and plural forms for all people, regardless of who we are speaking of (such as ourselves, or the second person form), when we are discussing what we like?
2. I really doubt that gustar is never conjugated in any cases other than the above mentioned one. What are some other ways in which you can conjugate gustar in a sentence?
7 Answers
One day I asked her about the conjugating of gustar, but she was a bit annoyed with all of my questions and told me not to ask any more of them!
(yo) gusto
(tú) gustas
(él) gusta
(nosotros) gustamos
(vosotros) gustáis
(ellos) gustan
One time she told me that you will never conjugate gustar, because it is always used in the infinitive form. Clearly, this is not true, or else we wouldn't say "mucho gusto".
Wrong. In "me gusta", the verb is conjugated (present indicative, third person singular). The verb is fully conjugated, like any other one, but the third person is by far the most common. By the way, the word "gusto" in "mucho gusto" is not a verb, but a noun.
More examples of gustar conjugated in other forms:
¿Te gusto? = Am I pleasing to you? (=do you like me')
¿Le gustas? = Are pleasing to him/her? (does he/she you like you')
¿Le gustamos? = Are we pleasing to him/her? (=does he/she like us')
Again, this verb is normally used to talk about other things or people that people like, and since those are described in third person, the 3rd person is the most common one. In English, "to like" is statistically used a lot more with "him/her/it" (3rd person) than with all other pronouns put together, but that does not mean that you cannot say "Do you like me'".
If you ever study Old English, you'll come across a verb to mean "like" that was used exactly like "gustar" in Spanish.
It's the same idea as the difference between when we say "my back hurts" and Spanish speakers would say "my duele la espalda"-"my back hurts me." Different way, same thing.
Different? "back" is the subject both in Spanish and in English. The only differences are that English uses the possessive (my), and Spanish the indirect object (me), plus the word order. Otherwise, the structure is practical identical.
You can also say "La espalda me duele".
The easiest way to use gustar is to not think of it as "like." That's gonna mess you up. It is "to please." There are a lot of things in spanish that seem "backwards" to us, but it's the same exact idea. You just have to remember you are not saying "I like him," it's "he is pleasing to me" in spanish. This seems simple enough until you get into a sentence like "he doesn't like me," which is "no le gusto"- "I am not pleasing to him." I almost told a woman I didn't like her baby when I was really trying to say I didn't think her baby liked me because of this! Haha
It's the same idea as the difference between when we say "my back hurts" and Spanish speakers would say "my duele la espalda"-"my back hurts me." Different way, same thing.
One time she told me that you will never conjugate gustar, because it is always used in the infinitive form. Clearly, this is not true, or else we wouldn't say "mucho gusto".
Wrong. In "me gusta", the verb is conjugated (present indicative, third person singular). The verb is fully conjugated, like any other one, but the third person is by far the most common. By the way, the word "gusto" in "mucho gusto" is not a verb, but a noun.
Upon considering why a Spanish teacher would make such an obvious blunder, I believe the context of the discussion must have been the usage of gusto as a noun in mucho gusto. The teacher may have been explaining that gusto is a noun form in its own right and not an (English) gerund. She was probably explaining that gusto was not an ing form of gustar and how Spanish uses the infinitve, never a conjugated form of the verb like (yo)gusto to express the noun form.
Welcome Rosalina:
Here are a couple of things you can do on this site:
Go to (Learn Spanish) at the top of this page; Go to (Learn Spanish 3); then go to (Learn Spanish 3.7 - Verbs like Gustar)
Type in "gustar" in the Search Box on this page and you will find discussions and examples.
but she was a bit annoyed with all of my questions and told me not to ask any more of them!
I am a teacher myself and one of the most important things I teach them : there is no stupid question but stupid people who do not ask when they have a question.
This is aimed at prompting them to ALWAYS ask!
This attutude of your teacher is really outrageous. 
What are some other ways in which you can conjugate gustar in a sentence?
We do not very often use gustar with other persons, but it is perfectly posible.
I can think of several sentences like the ones below.
Pedro y yo nos gustamos.
Pedro es muy majo...¿crees que le gusto?
To practise, have a look at these flashcards. 
Fisrt, I do not believe that your example of mucho gusto provides an example of when we conjugate gustar. Gusto is a noun in that usage and not a conjugated verb.
I have no idea what you teacher was referring to when she told you that gustar is never conjugated, but always used in the infinitive form. We'd have to have context. It sounds like she is referring to when gustar is used as a gerund for pleasing, but that's just a guess.
The answer to your first question requires an understanding of structure of the sentences employing the class of verbs like gustar. They are usually inverted from the normal subject+verb+complement declarative sentence. The subject of the sentence follows the verb. The verb is usually intransitive (no direct object). The indirect object normally proceeds the verb. To make this more comprehensible to the English speaker they translate gustar as is pleasing to as you mentioned.
Me gustan las manzanas. Apples are pleasing to me. Since the subject is always a noun, person, pronoun, nominative clauses, etc. the verb will usually be conjugated with the 3rd person. Apples (they) are pleasing...
To answer your 2nd question, Yes, gustar can be conjugated using other persons besides 3rd. Not being a native I don't know how common those constructions are (I don't see them that often) , but ¿Le gusto a ella? ...Does she like me? or am I pleasing to her? is grammatically correct and natural. And you could substitute gustas, gustamos, or gustáis for gusto in that sentence.
