I hate when I've just finished updating the Through the Ages spreadsheets and feel like I can Excel pretty hard but then I come here and theory and Kuildeous Excel harder than I can and I feel like I can't Excel very hard after all
I was a total Excel noob until fairly recently. Then, I wanted to do X, and it seemed like the only way to do X was some really stupid laborious way. Turns out there is a function that will do X easily and efficiently. Repeat.
Excel only needs to be learned through necessity. If you don't need VLOOKUP, you don't need to know it exists. The only quality you need is tremendous laziness, in that you would rather Google a problem than brute-force a dumb solution.
Incidentally, I do know VLOOKUP, and I've actually used HLOOKUP on occasion. SUMIF is totally new to me mind you.
And pivot tables. I know roughly how to do them, could probably work it out again given a few minutes.
Then you are hardly a noob
SUMIF is easy and does exactly what you'd think it'd do. It came in in 2007 along with IFERROR, two great functions.
I think Above-Competent would be mastery of pivot tables, FREQUENCY(), one-way/two-way data tables, VLOOKUP/HLOOKUP, and dynamic named ranges. But like I said, if you don't need to use those (for instance I haven't learned how to use one-way data tables because I haven't needed to), then you don't need to learn them.