Oh bother... I can play the quote game too...
What, you don't like the way I quote? I find it easier to find what is being talked about and am used to quoting this way when having a discussion about something. Though if you think that this is some "game" I'm fine with ending it here.
Yeah, so she does things. I said before that her story advance pretty well, but as a person she is still basically a blank page. It wasn't until the end of her contest arc, her 3rd season, that she finally started to grow as an individual. Her caring for Max so strongly truly came out of nowhere, yet was a breathe of fresh air. It was very nice to see her care about something for a change. May's expedition did give her something I guess. It built on her stupidity a bit. But truly, she just went from place to place doing whatever until Harely came around. That's when her character started to become something.
Stupid? She's ten. Ten year old play pretend. There are a lot of kids who play doctor or cops and robbers when they're young. It shows she's still childlike and enjoys her travels. Oh, and before Harley she was:
Impatient (left when Rowan's assistant said wait), adventitious (she said she was only interested in traveling in beginning), caring (when Torchic was gone and she found out she got upset and worried), gets things done (getting boat for Ash), and was unsure about self (begs Solidad for advice when Solidad says she'll be fine).
That's just it. She's always just "fine with whatever." never really has anything to say. Except shopping. I'll give you that, she likes to shop. SUCH PERSONALITY
She wasn't fine with badge getting. Her and Max argued that made him get lost in a mansion. She also got angry when Ash gave her advice. She was shown as impatient and whinny early on.
Again, she got better in the end of her Hoenn arc. She didn't even care to travel with Ash originally. Just did when her parents suggested it or whatever.
What? No. She's the one to push Ash to let her travel with her. If she did what her parents wanted, she would've collected badges like Ash did.
Wait wait wait, people see this as May liking Ash? Wow. This is quite interesting actually. I always wondered why anyone would ever pair up Ash and May when they can go 10 episodes without actually saying a word to eachother. Very interesting that you would interpret these moments as such. I've just watched these 3 seasons this past month and I truly never once saw any hints of May liking Ash. It certainly is a stretch, but it is what you make of it.
Well, I think the biggest hint was in the... Ranger movie was it? But yeah, I'm not really a big fan of Advance and like Contest much more. But yeah, all ships are mostly interpretation. Like you interpreting she had interest in Brock and not just that she was happy at that point that someone was able to cook everyone lunch and was just impressed by his knowledge with pokemon. But I do understand your confusion about a ship. You can look into what shippers think are hints and why they like it here:
http://bulbapedia.bulbagarden.net/wiki/Shipping:AdvanceShipping And from there you can check out other ships.
(and it's not like she showed off her Bikini to just Ash, Brock was there too after all, haha. Showing off to boys in general!)
She did it in front of Max & Ash looking between the two. I don't think she was showing off for her brother XD
But even ether way if she was showing off for Brock and Ash, she was still had to have some interest in Ash to want to show off around him.
Most of these examples hint at a person who is just going along, doing whatever without any real cares. She does learn to love pokemon and her journey grows and progresses, but her personality is always just "Ok, sure! Let's do that! Oh, a contest? I'll join that! Oh? lunch? Sounds good to me? Oh, you want my opinion? I'll be fine with whatever you want?"
I guess at the end of it all, she's got that hippie kinda, go with the flow personality, which really doesn't create an individual, just a person who is there. May was just there.
I'm not sure what you wanted from her? You wanted May to complain/argue about everything? Just because she's mostly fine with traveling with "doing whatever", doesn't mean she's personality less.
Also, a couple times during the beginning, she did tell Ash to slow down and made them take a break. So she wasn't "Ok! Fine!" all the time.