I am in total agreement with you here, I have often thought about using a HUD but the cost of some of the better ones out there do not reflect my personal buy-in amounts and I find that you could become more reliant on them and not learn anything.
One famous quote reads "Poker is a game you can pick up in 5 minutes, But it takes a life time to master" I have been playing Texas Holdem for over 25 years and I am still learning, and I may never be a great player, but I have had a great time learning.
Like every one else I have good days and bad but what makes me a good player is that I can survive a losing streak and get back on top with a little patience and perseverance.
When the fun Stops, STOP!