Heh, I've only got 9 hours and I've mumbled readbacks before...But the embarassing part was what I did afterward on the landing!
Like the last time I flew (Friday) The ATC gave me some serious information overload, and being the ADD case that I am, I was listening for the important stuff like heading, altitude, traffic, and sequence, so my readback was like this "Cessna xxxx, Maintain VFR approach heading 280, descent to 2,500feet, 3 mile left downwind 12L, behind Piper xxxx, Traffic in sight mumble mumble mumble..."
Yep, I dunno if it's a good thing or a bad thing, but I have gotten the hang of ATC, and can handle pretty much anything they've thrown at me thusfar... My instructor was pretty impressed with my ability to communicate and comply with ATC that day. (he said if ATC gave me too much to handle I could just say unable, student pilot, and ask for an easier approach, but I said I had it - to this day once I've never said student pilot on the radio)
so I got in the pattern, and came in for landing...(my 15th landing to date) it was my first smooth, good landing.. a few feet left of the center line, but I touched down like a pro.. softly landing my rear, main wheels, then lowered my nosewheel gently)... I was so amazed, I actually forgot to pull the power back for a few seconds and my instructor scolded me and took over)
I was so embarassed.... yikes!
The only other real bonehead move I did was when I had cessna traffic, same altitude, 3'o clock, and atc said piper traffic, 1 o'clock (they arent always dead accurate, at 3,000 on approach ,opposite heading).. I said traffic in sight, not realizing it was cessna and not piper, and wasnt flying the opposite way)...my instructor got on and said "Cessna xxx, and we do not have traffic in sight) and ATC told us to change heading and descent
Both those happened on the same day, And I was feeling pretty down on myself, but my CFI said It was nothing to worry about, just learn from..and that he'd seen way people do way worse than me, and those people now had licenses)