Should I give professor gift at the beginning of my PhD? I will be in a PhD program in Germany in which the first year of the program consists of only studying courses under several different professors. 

Some people suggested me that I should give gift to the professors with whom I had interview with at the beginning of my PhD. Should I do it? Would it be misunderstood as bribing?
I would prefer not get a gift from someone that is dependent on me. I don't want to end up in a situation of perceived (by the person receiving the gift, giving the gift, or by an outsider) bribery. I realize that in many cases it is an innocent show of appreciation, but just saying (or writing) "thank you" will achieve the same goal without the risk of it being perceived the wrong way.