Anything overused is a bore, but of course the appropriate situation requires the appropriate response. If one uses the phrases, “please and thank you” at times it’s not really appropriate, or to sound “phony” I would say yes, it can be overused. But if the situation is a giving situation and a lot of things are being given, say thank you the first time, then make a nice comment each time about the item, and at the end of opening the gifts, say thank you for all the wonderful things and comment about how much you will use them, even if you won’t. Manners are always appropriate no matter where you are, and are appreciated by the giver. A thank you note is always required even if you said thank you in person. A person will find they are given more things if the giver receives not only a thank you verbally, but a thank you note that must be sent snail mail!! Times change but manners don’t. If you are the giver, never say, “no problem.” That’s totally rude. As to “please”, say it any time you ask for something from anyone. Here’s 2 sites I found on google.com for you:

http://www.say-thanks.com/

http://www.ezinearticles.com/?Creative-Ways-to-Say-Thank-You&id=5254

An interesting story I found and pasted here:
Saying please and thank you
Saying please and thank you is something that is taken for granted here in the USA and other places.

I remember being struck as a teenager by Jonathan M. Ford’s take on such terms, through the eyes of a Klingonaase captain:

The Admiral got up from his chair. “Another?” he said, pointing at Krenn’s glass.

“Please,” said Krenn. He had had a hard time getting used to the word. But after a day on the Starbase, Krenn realized that the Humans used it continuously, across all levels of authority, for requests of any or no importance: the word simply had no meaning.

And then again a few pages later:

“So you were just following orders?”

“Do officers of the Federation not follow orders?”

Whitetree leaned forward, about to say something, then he sat back slowly. His expression had changed wholly, though the shifts of flesh were small. “I’m . . . sorry, Captain.”

Krenn had heard that word too: it seemed to have more of its meaning left than please did. And, watching the Human, Krenn thought he intended that it should have meaning now.

I was thinking about this last week while I was staying in a hotel and noticed once again that on ordering room service that a 17% gratuity was pre-calculated as a part of the bill (and of course there was an additional place for a tip if I wanted to write one in).

I was also thinking about time I spent in Ireland this Summer where the service in several restaurants was terrible and tips were almost never left by people. It is easy to hypothesize about the connection, though I doubt that the service for an institutionalized tip is any better (I was honestly not even sure that what the hotel called a gratuity even went to the employee or not; I also was not sure how best to find out the truthful answer on the topic, and never have).

And I was thinking about it again a few days ago when my sister-out-law Jenny was speculating about the strange interactions with a cashier who says thank you when you pay and then you say thank you for the change — there is not much time for more than that (without holding up the line!) and how truly sincere is it when it is a mechanical part of a transaction, no matter how polite everyone involved is?

So why did the word please seem to have no meaning to someone who was new to the language (well, ignoring the fact that it was obviously fiction, of course!)? Obviously the fact that it is used so often tends to water down the meaning, until it is almost brought down to the level of a particle in English — a sound that you say at certain times because it is sort of expected.

I stopped using the word please for the most part except when it is emphasized as a point of sarcasm. I joked with people that saying please in this context anticipates that something will be done without it happening, whereas saying thank you in a warm tone may make it clear that it really is appreciated (and is most commonly said after something is done anyway). But under the joke was the serious notion that there is really no way to impart meaning into the word please without implying that you think someone might not do what you are asking. And how often will that truly happen?

Now of course thank you has its own watering down that happens, but not as much as please, in part because you can say it with some feeling (kind of like I’m sorry, now that I think about it). You can, in a sense, impart some pragmatic content to your words with your tone of voice — something that may be implied in words that are read, depending on the circumstances being described.

So, according to dictionary.com, the linguistic meaning of the word particle is:

An uninflected item that has grammatical function but does not clearly belong to one of the major parts of speech, such as up in He looked up the word or to in English infinitives.
In some systems of grammatical analysis, any of various short function words, including articles, prepositions, and conjunctions.
I think it is easy enough to at least consider that most inflections of please might be considered particles now.

The most ironic part for me was how in Hebrew, the same word (בבקשה) is used for both please and thank you. I have not really tried too hard to figure out what that means, though there are other items in the Hebrew language that have similar simplifications (there are fewer prepositions, for example — you can often tell if someone is still translating in their mind from Hebrew to English if they confuse in and on, for example). But with בבקשה (b’vakashah) I wonder if Hebrew has made it less of a particle than it seems to have become in English….