Although I've defended your position in a previous post, I think your arguments here are indefensible.
2. Not stealing a pack of gum from WalMart
That's not "good". It's just "not bad". I would say this is morally neutral
Stealing (even from WalMart) is considered morally wrong in all societies. It may sometimes be justified, but it is never considered morally right or even morally neutral. If your definition of morality fails to allow for this fact, then there must be something wrong with your definition.
If you steal from me, that reduces my happiness; if I steal from you, that reduces your happiness. As a society, therefore, we voluntarily agree not to steal from one another, so that we can enjoy our possessions in peace. That voluntary agreement is enacted as a moral prohibition against the act of stealing, so that any such act, in whatever circumstances, attracts social and even legal punishment.
1. Picking up a piece of trash out in the woods
I would say such an act is morally neutral. Why do you say it is morally good? I can see it being morally good if you add some more information such as:
-the wood was dying from pollution. In which case "the being" you're helping here is the wood itself. I was trying to be careful and not use the word "person" so as to include any living creature. Including plants.
Again your purely psychological definition of morality is leading you astray. Fifty years ago you could have argued that leaving trash in the woods was a morally neutral act; but nowadays, when it's morally frowned upon and even illegal in some countries, it certainly isn't considered morally neutral.
Morality, in the main, is something decided upon by society as a whole, not by individuals. You don't get to decide that stealing or leaving trash in the woods are morally neutral. If you carry out either of those acts, and you get caught doing them, you'll suffer the appropriate social sanction, whatever your personal views.
3. Stopping the boiling water from spilling on the baby
Not being able to read the future, I won't be able to say that this baby is going to be incredibly thank-ful or not. Chances are though, once they are capable to express their thanks, they would.
Stopping a baby from being scalded by boiling water is a good thing. Everybody knows that. If your definition of morality has difficulty explaining why it's a good thing, then there's a problem with your definition. Don't waste your time trying to wriggle around the question, just adjust your definition.
The simple explanation of why it's considered a good thing is just that stopping people being harmed is a good thing. You don't need to create fanciful theories about the internal psychological state of the people (or babies) affected. Getting scalded hurts, and stopping someone from getting hurt, other things being equal, is always a good thing.
'I can't even fit all my wife's clothes into a suitcase for travelling. So you want me to believe we're going to put all of the planets and stars and everything into a sandwich bag?' - q3psycho on the Big Bang