Learn English – A polite way to let people go in front of you in a checkout queue

A simple apology.
Here is a simple way of saying what happened.

I'm sorry. I overslept.

This explanation might avoid punishment once.

One interpretation: An apology is a promise.
Many people believe that a genuine apology includes:

• acknowledging that you were wrong.
• admitting to what you did wrong.
• genuinely trying to understand how you harmed (or inconvenienced) others.
• thinking about what you did, to find what you could have done differently.
• consistently endeavoring in the future to avoid making that mistake, so that if a similar situation occurred in the future, you would not harm (or inconvenience) others.

"I'm sorry", with an acknowledgement of what you did wrong, can be interpreted as such a genuine apology. If you make the same mistake again (and inconvenience the same person(s) again in a similar way), people will doubt whether your apology was sincere.

Thus, "I'm sorry" raises the stakes -- it can change an issue from a matter of politeness or inconvenience to a matter of honor, honesty, and integrity.

Another interpretation: An apology is a polite noise.
Many other people think "I'm sorry" is just a polite noise people make to acknowledge inconveniencing someone. Unfortunately, you cannot know in advance whether the person you are talking to interprets apologies as "mere words", or as sincere promises to avoid making the same mistakes.

There are many, many different ways to thank someone politely.

The ways that you have listed are all more or less correct (minus a few grammatical errors) and any native English speaker would appreciate the effort you put into thanking them.

Numbers 1 & 3 are pretty much perfect, but i wouldn't use number 2 as it sounds too broken.

if i were to say numbers 1 & 3 respectively, i would say them like this:

1) Thank you for taking the time to share your knowledge with me.

3) Thank you so much for taking the time to share your knowledge with me.

Alternative ways of thanking someone:

1) Thank you so much for helping me.

2) I greatly appreciate the time you've taken to share your knowledge with me.