While I found enjoyment in software development at a younger age before Maniac Mansion even came out, adventure games did have an important effect. These included text adventure games that I played, Sierra on-line quests, and later on Lucasfilm/arts games.
Some of my development efforts at the time revolved around writing my own adventure games that I developed with a friend of mine. I was in charge of the programming, he did the graphics and music. This was done on PC (8086/8088, CGA), and it was basically a text adventure with graphics (a-la the Hobbitt, and other games of the era). A later effort would include a character that would walk around, in front and behind objects on the screen. Doing that required lot’s of learning and invention on my part as I didn’t have any official training, or anyone to really learn from. It was really hacking into the environment, observing, taking little bits from here and there. Some of the things that are now trivial to do were much more complicated. There was a limited amount of memory to use, the pixel to memory mapping wasn’t trivial (for me at least) – interlaced, 4 pixels per byte (CGA). What motivated me was the idea that someone else already figured it out, so playing these graphical adventure games really pushed me.
Some other experience that I mentioned it once elsewhere – I didn’t have (up until a few years ago) a legitimate copy of Maniac Mansion (or any other game at the time; where I lived there was no where I could buy any, and even if there was I never had any means to buy anything). So I couldn’t really finish the game because there was a copy protection in the form of a keypad and a code that you needed to punch in. I worked around it by hacking and disassembling the game, removing that copy protection. Modified the function that handled that keypad to return true, or something like that. (as a side-note: the problem iirc is that the function was used for all the keypads in the game, so it pretty much opened up areas that I wasn’t supposed to go into and made the game extra short and easy). This type of experience was not unique to MM, it was one out of many that taught me a lot. It was all part of the experience I gained through middle and high school, and these games certainly helped. Later on when I went into college and afterwards, all that experience pushed me ahead.