The poem "Mont Blanc" indeed had the nature being imagined vividly, with a mixture of admiration and fear. Since humans never really understand nature fully, we tended to confused between the lines of reality and fantasy in understanding it, especially during the poet's time where scientific advancement had yet to reach its maturity in explaining nature. Therefore, the imagination was something understandable, considering how the nature was something beautiful and majestic, like a higher being, yet also being destructive like with its "fiery flood". The poem really tied in how he imagined nature and his feeling toward it.
The poem "Piano" was relatively simple and short, yet delivered the poet's feeling completely. The sense of regret was heavy here indeed, where he remembered his childhood memory and feeling. Rather than embarrassed, I felt that it was more of avoiding hurting himself when he remembered it and felt "betrayed". Indeed, he was well aware of him being an adult, yet him casing his "manhood", was, as I believed, him attempting to relieve in his childhood memory than living the present.