In "Toads," it isn't too tough to tell that the speaker is dissatisfied with his life. He might not say the words, "I feel a great sense of dissatisfaction when I look at my life," but there are plenty of other clues letting us guess that's probably what he's feeling. (Perhaps the biggest clue is the fact that this is a poem by Larkin—his speakers are dissatisfied with something most of the time.)
The speaker's sense of dissatisfaction is so profound because it comes from external as well as internal sources. If it were just one or the other he might have a shot at a fulfilling life, but as it stands, there's no hope. Yay.
Societal expectations are the primary source of the speaker's sense of dissatisfaction. If the speaker didn't have to spend "six days of the week" working to provide himself with basic necessities, he would be able to fill his life with more fulfilling pursuits. In other words: quit your day job, dude.
The speaker in "Toads" is feeling stuck for a couple of different reasons. First of all, he's got that ugly toad (work) squatting on him. It keeps him from getting what he wants out of life. He feels confined by it and he wants to find a way free from it. The trouble is, he's got one of those toads in him as well. (What, did he swallow it or something?) It turns out that getting free from both of these toads might not be possible.
Relax, fella. The speaker's sense of confinement is all in his head. It is a personality flaw. Societal demands and obligations are not to blame.
No escape—the form and structure of "Toads" mirrors the sense of confinement that the speaker feels.
The speaker in "Toads" seems to think his one shot at getting rid of the metaphorical toads that torment his life comes in the form of wit. He figures maybe, just maybe, he can use his smarts, his cleverness, to "drive the brute off." He has lots of evidence to support wit's power against the amphibian foes, but in the end even wit proves useless for our poor speaker. Oh, well—good try?
Nice try, guy, but the speaker's argument that "lots of folk live on their wits" is flawed. All of the examples he gives of people living on their wits actually involve real work of one kind or another. It is just the speaker's perception of these other lives, and a "grass is always greener" mentality, that makes it seem to him like they've got it made.
The speaker can't get free of "the toad work" because he is a coward. Wit has less to do with it than bravery, gang.
Big plans? Hopes and dreams? We've all got 'em. Unfortunately, as the speaker in "Toads" discovers, things don't always work out the way we'd like or the way we plan. He wants to have a fulfilling life. He hopes for the Big Three: fame, fortune, and someone to share it all with. But instead he gets a bunch of toads. How unfair.
Sorry, but the speaker's realization that he will never achieve all he hoped and dreamed of is nothing new or particularly special. It is symptomatic of a common condition: being alive. Most people are, like this speaker, prone to disappointment.
"Toads" presents a problem of perspective. The speaker feels unfulfilled because he can't get everything he hopes for: fame, fortune, and love, all at once. (He doesn't ask for much, does he?) But the poem implies that he can have these things separately. Sometimes, like the poem's speaker, we are too stubborn to realize that we have in fact achieved our goals, just not exactly as we had envisioned we would.