Limit One....Coupon Confusion!

Alright. First of all, disregard that in the coupon example above it says, "Valid for use in Canada only". This is a coupon I got off Google images to help me explain my issues....I hope if you know me, you know that I try to be an honest person. I never (usually) try to deceive anyone or get something for free that I shouldn't. So, I need some help. As I mentioned a while back, I've been using coupons - buying the paper on Sundays, using the coupons out of it only when combined with sales Kroger, Publix, or WalMart have. So...this is sort of like a double savings - using the coupon + the item already being on sale. I've been having a problem though and getting confused about some things. Okay, one really good thing about shopping at Publix is that if they have a buy one get one free sale, you can use two coupons for that. So, last night at the store, they had Yoplait yogurt on sale - 20 yogurts for $10.00. Well, I have coupons for that. So, I try to give the cashier 6 coupons that all say "Buy 6 Yoplait yogurts, get $.40 off". Well, I thought I could give her 6 coupons. Like, if you took an individual coupon and put it on one yogurt, I would have bought 6. Then, if you took another coupon and put it on another yogurt and counted, you would still count 6. Well, they informed me I could not do this. I know that was confusing and you may not have understood. This next thing should be easier to understand. Just like I have circled above, most of the coupons say, "Limit One coupon per purchase per visit". Well, if I have another coupon - like the other day with Soleil razors - I had a $3.00 off coupon that said the message above, and then I had a $2.00 coupon that said the message above. Well, because they were two different coupons, I used them both - and they let me, but I felt like she was looking at me like I was trying to be shady. I'M AN HONEST PERSON! I just want to take the greatest advantage of the coupons I can, and I'm trusting the cashier to tell me if I can't use certain ones! This coupon business is fun, but very confusing. So, last night I shopped at Publix and paid $17.55 for the groceries - and I saved $14.56. This is very good - but not good enough! I really want to always save at least 50%, but hey, I'm doing the best I can, and I'm improving! But, I just want you to know I'm not trying to be tricky or dishonest....
And one more thing. Did you know that after you buy all that food and get great deals, you actually have to eat it?? Our pantry is very full right now from all the things on sale I've been buying :) Uh, newsflash, we do need to eat the food for it to be worth it. So, I set out stuff to make chicken pot pie in the next few nights - maybe tomorrow night. Just need to get some chicken to boil first. Then, I need to work on the big boxes of chicken broth I bought - we just do not have enough room in our kitchen to store all these items! We must eat at home more! But NOT TONIGHT - haha....we're going to Brad and Joy's house for dinner tonight...maybe we'll eat at home tomorrow night...