<human>: Can you give me a shortened version of the text?

So here's a random plumbing question that hopefully someone with more plumbing experience could answer for me.

My shower doesn't get as hot as it used to be.  I live in a three story condominium (two floors and a finished basement).  The hot water heater is in the basement - it's already turned up to the maximum.  I have a half bathroom on my first floor which has no temperature problem.

In my full bathroom (on the top floor) the sink has no temperature problems.  The shower and tub, however - literally one foot away from the sink - only get lukewarm, at best.  It got hot enough during the summertime, but it has gradually gotten a little bit cooler steadily since then.  

I know NOTHING about plumbing, does anyone else have any ideas as to wtf the problem is?
<bot>: my shower used to get as hot as I wanted.  It gradually has gotten cooler and is lukewarm at best.  My hot water heater is at max, and my sinks all get as hot as I like.