The feeling is like something less of being smug. This happens when natives complement you about your fluency and accent. But of course as the saying goes, don't sit on your laurels or bask on your own glory. There are still a lot to learn. To learners, the initial difficulty come with conjugation, concordance with number and gender, use of subjunctive and understanding a native in real-life setting. Speaking it well is like getting a pat on the back of hearing ''Way to go, buddy.''

I would have to say (as a native speaker) it's really nice to hear someone using all the proper words, like adjectives, as bloke chap said, the right gender (which is a really important part of spanish words), etc. using all those elements in the right way, complementing it with a proper pronunciation (for example the r's and the vowels) gives the impression of someone who really understands the language, and therefore when someone recognizes that, you can be sure you're doing it well. Adio' señorita.

Sorry, it should have been... back or hearing... and not ''of'' in the last part.