I don't understand you because you speak bad Italian

I am very lucky to have grown up bilingual(ish). I am further fortunate in that one of the languages I happen to speak (French) is very similar to Italian. So many of the verbs in Italian are similar to French: Mangiare, Parlare, Ritornare, Entrare and sometimes English: Stressare (seriously, that is the infinitive form of the Italian verb which means to be under stress). In fact, hubby and I often entertain ourselves by looking for words that are completely different in all three languages, my favorite in the word German (allemand, tedesco). However of course there are important differences in Italian such as, for example, in French the formal/polite voice is second person plural as in "Comment allez vous?" whereas in Italian it is third person singular "Come sta?" and strangely (to me) the female form of third person singular is used for the formal/polite voice regardless of the gender of the person in question. Anyhow my major source of errors & embarassment when speaking in Italian stems from the fact that Italians do not typically use pronouns. So, for instance, rather than saying "You are late", they would simply say "Are late". This works far better in Italian than English (in fact it doesn't work at all in English) because in Italian the verb endings are different for the various people so the listener knows who is being referred to despite the absence of a pronoun by the ending of the verb. Enter my difficulties. I am forever mixing up the endings for first & third person singular and thus have developed the incredibly ANNOYING habit of referring to myself in third person. It would at least be tolerable if at least I were consistent however several weeks ago I was in the grocery store. To set the scene, I was trying to bag my groceries, scramble for money with baby strapped to my chest. The woman in line behind me began to speak to me in rapid fire Italian. Now, if I have a context... if I know what a person is likely to be talking about than I can follow about 60% of what is being said. (If the person is talking about babies or running than that percentage jumps to 80% ish). However the random, out-of-context conversation by stranger who doesn't know how poorly I speak Italian is a source of much stress and very little comprehension for me. Anyway I was struggling with groceries, bags, money, baby and very cognizant of the many people in line behind me as this woman began speaking to me quite insistently. Finally in desperation I tried to tell her that I didn't understand her because I speak very bad Italian. Sadly, I got the verb ending correct for the first verb (understand) but not for the second verb (speak) and wound up telling her that I didn't understand her because she spoke very bad Italian. Ouch.