The aspirin/pseudofed/caffeine produces a very nice morning sensation of wakefulness far superior to a normal cup of coffee.

Coffee consumption tends to be highly variable. I tend to drink it black, which makes it rather slow to consume. Or if I sweeten it and add milk I'll drink it faster. In any event there is no guarantee that I'll actually drink all of it.

I noticed the last time I switched to caffeine tablets over coffee that when I had forgotten to take my morning tablet, after a few days, that it had no effect on me. The usual morning headache and grogginess was absent.

Something about the classical conditioning process involved in the time it takes to consume the coffee, the smell of the coffee, and so on, seems to be important to the withdrawal effects.

Here is a random picture from wikimedia commons: